Labels:text | child art | screenshot | art OCR: FT. JEFFERSON, GARDEN KEY, DRY TORTUGAS ISLANDS, 1846 Ft. Jefferson, the largest of the 19th-century masonry coastal fortifications, was erected by the U.S. government to control the Straits of Florida and was garrisoned during the Civil, Spanish-American and both world wars. Walls are 8 feet thick and 50 feet high. National Monument 1935, National Register 1970. Photo courtesy of Florida Department of Commerce, Division of Tourism.