The Similan Islands are a group of islands in the Andaman Sea in southern Thailand. In 1982 it was commemorated as a national park titled Mu Ko Similan. Attractions there include Ko Similan, which is the largest island and is filled with a diverse species of fauna such as flying foxes and mangrove monitor lizards. Other attractions are the widest beach in the park, Ko Huyong, which is home to many sea turtles, and the dive sites scattered throughout the Similan Islands. The dive sites vary from sloping coral reefs to underwater granite boulders that visitors can swim amongst. One of the most popular dive sites is Richelieu Rock, which is filled with an abundance of marine life.