What began as part of a 19th century plan to help protect the southeastern coast of the United States, became Ft Zachary Taylor or just "Fort Zach" for short. During the Civil War, the Union actually seized control of the fort, to prevent it from falling into the hands of the Confederate Army. Originally the fort was completly surrounded by water, with just a small walkway connecting it to the rest of Key West. The fort was completed in the late 1860's, though the upper level was destroyed in 1889 to make way for newer weaponry. The old cannons were then buried within the new outside wall, so that they could save on building materials.