The Florida Keys are a coral cay archipelago of tropical islands. They form about 120 miles of the southernmost portion of the country, between the Atlantic Ocean and Gulf of Mexico. Visit Dry Tortugas National Park, which is accessible only by boat or seaplane but has some of the best beaches in the country, go on a boat tour, or learn about nature by visiting the Key West Butterfly Conservatory. Adventure –seekers can go scuba diving to explore shipwrecks or snorkeling to see amazing marine life.