The underwater world is a marvel in many places. Gregg Johnston, travel editor of Sport Diver Magazine, recommends some of his favorite snorkeling spots:

He likes the Florida Keys:

"Long Key State Park, 10 miles (16 kilometers) south of Islamorada, is a prolific multiacre garden of finger coral. It's home to tiny neon-colored tropicals. You can just float by and gawk at the kinetic masterpiece as it passes by."

Outside the United States, he likes Bimini, in the Bahamas:

"The Bahamas are a snorkeler's universe all by themselves. There are more than 700 islands scattered over 100,000 square miles (260,000 square kilometers) of ocean. This means thousands of miles of reef-encrusted shoreline and countless tons of marine life. For snorkelers, Bimini even offers clues to the lost city of Atlantis. The Bimini Road is a sunken stretch of symmetrical, flat stones that can be easily explored. You can also splash around with native spotted dolphins."