20 U.S. Destinations You Won’t Believe Are Real

Dry Tortugas National Park, Monroe County, Florida

Where to fly: Key West International Airport (then hop on a boat to get to the remote island)

You can only get to Dry Tortugas National Park via boat—but it’s well worth the trek. The park is home to Fort Jefferson, one of the biggest 19th-century forts. After you’re done reveling in the history, take a swim—or even try your hand at snorkeling and diving.