DRY TORTUGAS

the last seven in a long string of coral islands (keys) and sandbars that extend westward from Key West (in Monroe County), at the tip of southern Florida, U.S., into the Gulf of Mexico. Ponce de Len discovered them in 1513 and named them for the tortoises that abounded there. Later, mariners added the accurate adjective dry. A lighthouse was constructed on Garden Key in 1825 and another, on the largest key, Loggerhead, in 1856. The unfinished Fort Jefferson (184676) on Garden Key is the largest all-masonry fortification in the Americas. It remained in Union hands during the American Civil War and served as a prison until 1873. Among the prisoners was Samuel A. Mudd, sentenced for complicity in the assassination of Abraham Lincoln because he had set John Wilkes Booth's broken leg. Possessing abundant bird and marine life, the fort and islands were proclaimed a national monument in 1935 and became a national park in 1992. The park, with a land and water area of 101 square miles (262 square km), is only accessible by boat or seaplane.