Krabi, one of the southern provinces of Thailand is also called the "Emerald of the Andaman". Krabi is an area of outstanding natural beauty. Most notable are the solitary limestone hills, both on the land and in the sea as islands. Rock climbers from all over the world travel to Ton Sai Beach and Railay Beach to climb. These beaches form part of Krabi's Phra Nang Peninsula. Of about 154 islands belonging to the province, Ko Phi Phi Leh is perhaps the most famous, as it was the set of the movie The Beach. The coast of the province was badly damaged by the tsunami on December 26, 2004. The limestone hills contain many caves, most having beautiful stalactites and stalagmites. The caves also have one of the oldest traces of human occupation in all South-East Asia. Ao Nang Beach, is Krabi's most developed beach. Diving & Snorkeling, sea kayaking, Rock climbing, bird watching, sailing & cruising etc are some of the touristy activities at Krabi. Krabi town is very close to the river mouth that opens to the great Andaman Sea.