fort Jefferson, built in 1861, which stands on garden key, was a navy base until world war one .. today it's part of dry tortugas national park .. it sits roughly 60 nautical miles west of key west .. it is a civil war era massive structure that was built to combat piracy in the Caribbean .. it's the largest masonry structure in the western hemisphere, and the place where Dr. Samuel Mudd was incarcerated for treating the injury of John Wilkes Booth .. Booth, Abraham Lincoln's assassin, broke his leg when he jumped to the stage, after shooting him in the back of the head .. back in the mid 1970's, when i was visiting there a lot, it was usually deserted and and wonderful place to spend time..