Thailand's attractions include diving sites, sandy beaches, hundreds of tropical islands, nightlife, archaeological sites, museums, hill tribes, flora and bird life, palaces, Buddhist temples and several World Heritage sites. Many tourists follow courses during their stay in Thailand. Popular are classes in Thai cooking, Buddhism and traditional Thai massage. Thai national festivals range from Thai New Year Songkran to Loy Krathong. Many localities in Thailand also have their own festivals. Among the best-known are the "Elephant Round-up" in Surin, the "Rocket Festival" in Yasothon and the "Phi Ta Khon" festival in Dan Sai. Thai cuisine has become famous worldwide with its enthusiastic use of fresh herbs and spices.