Have you seen the horror-comedy film Piranha? If you're interested in diving the famous lake (free of flesh-eating fish, of course), then Lake Havasu is for you! The expansive lake located on the California-Arizona border, is like a freshwater scavenger hunt for scuba divers.

The Bonaire Reef Pilot Project is a model for the Caribbean. Check out the work of the Coral Restoration Foundation at Buddy Dive Resort's house reef.

Hard to spot and even harder to look away from, creatures like the tasseled anglerfish, stargazer, red-lipped batfish and reef stonefish are among the most unsightly species in the underwater world.