United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 ...
Significance: The Potomac Power Plant was an innovative small hydroelectric facility that operated from 1899 to 1991, originally as part of a wood pulp mill (built 1888), and solely as a power house after a fir... More
Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 ...
Significance: The Potomac Power Plant was an innovative small hydroelectric facility that operated from 1899 to 1991, originally as part of a wood pulp mill (built 1888), and solely as a power house after a fir... More
Fuerte El Abanico, Boulevard Norzagaray, San Juan, San Juan Municipio,...
Significance: It was built 1779-1783 by military engineer Thomas O'Daly, Chief of the Spanish Corps of Engineers in San Juan. It is a bastion-fort in the outer works of Castillo San Cristobal, a fan-shpaed desi... More
Fuerte El Abanico, Boulevard Norzagaray, San Juan, San Juan Municipio,...
Significance: It was built 1779-1783 by military engineer Thomas O'Daly, Chief of the Spanish Corps of Engineers in San Juan. It is a bastion-fort in the outer works of Castillo San Cristobal, a fan-shpaed desi... More
Dry Dock Engine Works, 1801 Atwater Street, Detroit, Wayne County, MI
Significance: The Dry Dock Engine Works is significance, first of all, because of its role in manufacturing and repairing marine steam engines and boilers for Great Lakes freighters and passenger vessels from 1... More
Dry Dock Engine Works, 1801 Atwater Street, Detroit, Wayne County, MI
Significance: The Dry Dock Engine Works is significance, first of all, because of its role in manufacturing and repairing marine steam engines and boilers for Great Lakes freighters and passenger vessels from 1... More
Dry Dock Engine Works, 1801 Atwater Street, Detroit, Wayne County, MI
Significance: The Dry Dock Engine Works is significance, first of all, because of its role in manufacturing and repairing marine steam engines and boilers for Great Lakes freighters and passenger vessels from 1... More
Dry Dock Engine Works, 1801 Atwater Street, Detroit, Wayne County, MI
Significance: The Dry Dock Engine Works is significance, first of all, because of its role in manufacturing and repairing marine steam engines and boilers for Great Lakes freighters and passenger vessels from 1... More
Timothy & Mary C. Healy House, 1415 Third Avenue, Altoona, Blair Count...
Unprocessed Field note material exists for this structure: FN-317 Survey number: HABS PA-5839 Building/structure dates: 1895- 1896 Initial Construction
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
North Casemates, Boulevard Norzagaray, San Juan, San Juan Municipio, P...
Significance: The massive fort of San Cristobal, located on the northeast corner of the old walled city of San Juan, was begun around 1633. An important link in the chain of defensive works of the city, it was ... More
White Haven, 7400 Grant Road, Affton, St. Louis County, MO
Unprocessed Field note material exists for this structure: FN-8, FN-22, N69 Survey number: HABS MO-1150 Building/structure dates: 1808 Initial Construction National Register of Historic Places NRIS Number: 79003205
White Haven, 7400 Grant Road, Affton, St. Louis County, MO
Unprocessed Field note material exists for this structure: FN-8, FN-22, N69 Survey number: HABS MO-1150 Building/structure dates: 1808 Initial Construction National Register of Historic Places NRIS Number: 79003205
White Haven, 7400 Grant Road, Affton, St. Louis County, MO
Unprocessed Field note material exists for this structure: FN-8, FN-22, N69 Survey number: HABS MO-1150 Building/structure dates: 1808 Initial Construction National Register of Historic Places NRIS Number: 79003205
White Haven, 7400 Grant Road, Affton, St. Louis County, MO
Unprocessed Field note material exists for this structure: FN-8, FN-22, N69 Survey number: HABS MO-1150 Building/structure dates: 1808 Initial Construction National Register of Historic Places NRIS Number: 79003205
White Haven, 7400 Grant Road, Affton, St. Louis County, MO
Unprocessed Field note material exists for this structure: FN-8, FN-22, N69 Survey number: HABS MO-1150 Building/structure dates: 1808 Initial Construction National Register of Historic Places NRIS Number: 79003205
Entrance Gate, Boulevard Norzagaray, San Juan, San Juan Municipio, PR
Survey number: HABS PR-56 National Register of Historic Places NRIS Number: 66000930
Entrance Gate, Boulevard Norzagaray, San Juan, San Juan Municipio, PR
Survey number: HABS PR-56 National Register of Historic Places NRIS Number: 66000930
Fuerte El Abanico, Guardhouse, Boulevard Narzagaray, San Juan, San Jua...
Significance: This structure is an excellent example of mid-19th century garrison architecture. It was first used as a guardhouse and later as a carriage shed. The building has been considerably modified, parti... More
Quarters No. 209, Boulevard Norzagaray, San Juan, San Juan Municipio, ...
Survey number: HABS PR-60 National Register of Historic Places NRIS Number: 66000930
Fuerte El Abanico, North-East Gate, Boulevard Narzagaray, San Juan, Sa...
Significance: This structure provides access from the north east glacis to El Abanico and La Princesa. It was probably built before the Spanish-American War of 1898 and it typical 19th century military architec... More
Michigan Island Light Station, Keeper's Quarters & Lighthouse, La Poin...
Unprocessed Field note material exists for this structure: N45 Survey number: HABS WI-317-A
Michigan Island Light Station, Keeper's Quarters & Lighthouse, La Poin...
Unprocessed Field note material exists for this structure: N45 Survey number: HABS WI-317-A
Casa Blanca, San Sebastian Street (West End), San Juan, San Juan Munic...
Significance: Casa Blanca was built as a residence and fort for Juan Ponce de Leon and his family, although de Leon died in an expedition to Florida without ever getting to occupy the structure. He was the firs... More
Chisos Basin Store, Castolon, Brewster County, TX
Significance: The Chisos Basin Store, built as a temporary structure in 1941 or early 1942, is constructed of adobe in a vaguely Spanish style, part of a larger complex with this architectural theme. After the... More
Chisos Basin Store, Castolon, Brewster County, TX
Significance: The Chisos Basin Store, built as a temporary structure in 1941 or early 1942, is constructed of adobe in a vaguely Spanish style, part of a larger complex with this architectural theme. After the... More
Marshall Space Flight Center, Saturn V S-IC Static Test Facility, West...
The name of the survey was changed from "Saturn 1-C Static Test Facility" to "Saturn V S-1C Static Test Facility" to more accurately reflect its name. Significance: Engineers used the S-IC Test Stand to help de... More
Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mo...
Significance: The Standard mill is significant as an intact example of the "model California stamp mill" that developed from the flowering of nineteenth-century developments in mining and milling technologies i... More
Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mo...
Significance: The Standard mill is significant as an intact example of the "model California stamp mill" that developed from the flowering of nineteenth-century developments in mining and milling technologies i... More
William & Amanda Kantner House, 808 Lexington Avenue, Altoona, Blair C...
Unprocessed Field note material exists for this structure: FN-308 Survey number: HABS PA-5805 Building/structure dates: 1886 Initial Construction
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Mu...
Significance: Production of Ammonium Nitrate. / Built as a war measure for the production of ammonium nitrate, a key component in high explosives, U.S.N.P. No. 2 became one of the largest plants of its kind wit... More
Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 ...
Significance: The Potomac Power Plant was an innovative small hydroelectric facility that operated from 1899 to 1991, originally as part of a wood pulp mill (built 1888), and solely as a power house after a fir... More
Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 ...
Significance: The Potomac Power Plant was an innovative small hydroelectric facility that operated from 1899 to 1991, originally as part of a wood pulp mill (built 1888), and solely as a power house after a fir... More
Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 ...
Significance: The Potomac Power Plant was an innovative small hydroelectric facility that operated from 1899 to 1991, originally as part of a wood pulp mill (built 1888), and solely as a power house after a fir... More
Fuerte El Abanico, Boulevard Norzagaray, San Juan, San Juan Municipio,...
Significance: It was built 1779-1783 by military engineer Thomas O'Daly, Chief of the Spanish Corps of Engineers in San Juan. It is a bastion-fort in the outer works of Castillo San Cristobal, a fan-shpaed desi... More
Dry Dock Engine Works, 1801 Atwater Street, Detroit, Wayne County, MI
Significance: The Dry Dock Engine Works is significance, first of all, because of its role in manufacturing and repairing marine steam engines and boilers for Great Lakes freighters and passenger vessels from 1... More
Timothy & Mary C. Healy House, 1415 Third Avenue, Altoona, Blair Count...
Unprocessed Field note material exists for this structure: FN-317 Survey number: HABS PA-5839 Building/structure dates: 1895- 1896 Initial Construction
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Wilson Dam & Hydroelectric Plant, Spanning Tennessee River at Wilson D...
Significance: In 1918, by the directive of the U.S. War Department, the Army Corps of Engineers began construction on Wilson Dam, a large hydroelectric project that was to supply power to U.S. Nitrate Plant No.... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More
Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan,...
Significance: This fort is one of the three defenses erected to protect Spain's first permanent colony in the present territory of the United States. Unprocessed Field note material exists for this structure: ... More