It's not the easiest place to get to, but if you're up for an adventure, take a day trip to Dry Tortugas National Park.
Located 70 miles west of Key West, Dry Tortugas National Park is actually closer to Cuba than the United States.
Discovered in 1513 by Juan Ponce de Leon, the park can only be reached by seaplane or boat.
There is plenty to see and do at the Dry Tortugas National Park, including snorkeling, fishing, boating, and touring the site's historic Fort Jefferson.
Visit the park’s website for more information at https://www.nps.gov/drto/index.htm