Today we're at Molokini Crater. This pleasant crescent in the Pacific Ocean lies in the 'Alalākeiki Channel between the Hawaiian islands of Maui and Kaho'olawe. The islet is all that remains of a volcano that erupted about 230,000 years ago. According to Hawaiian mythology, Pele the fire goddess was in love with a man named Mo'o. The trouble was that Mo'o was in love with another woman. Pele's revenge was typically violent: She cut her rival in two, her body becoming Molokini, while her head became Pu'u Olai, a cinder cone on Maui.

Molokini Crater these days is a prime scuba and snorkeling destination; the islet's crescent shape protects divers from waves and currents, allowing them to enjoy the reef. This habitat is home to at least 250 species of fish, including black triggerfish and parrotfish, as well as 38 species of hard coral, and some 100 species of algae. So, come on in, the water's lovely. Just be sure not to anger Pele.