Dams under construction. Watts Bar Dam, shown here under construction, has a semi-outdoors type powerhouse with an enormous gantry crane (to the right of the picture) for installation and removal of units. The project is further distinguished by a control building which is entirely removed from the hydro plant, being located some 120 feet higher on top of a steep cliff and with direct connection to the switchyard behind. The windowless left wing of the control building houses the control room; the tower-like structure in the back accomodates air conditioning, restrooms, etc. The glass wall, upper level, contains the reception room with a broad semi-circular overlook terrace, the story below the terrace devoted to offices