Cambodia is rich in both tangible and intangible cultural heritage. In terms of the tangible, scattered throughout the Kingdom are many prehistoric and historic sites brick, laterite, and sandstone temples, irrigation systems, and other cultural elements. To date, two Cambodian archaeological sites have been registered as World Heritage Sites, the Angkor region in 1992 and the Preah Vihear temples in 2008. At the same time, the Kingdom also has many different forms of intangible cultural heritage, such as arts and crafts, traditional music and dance, traditional customs, and ritual practices. Of the many living heritage elements in Cambodia, UNESCO registered the Royal Ballet of Cambodia and the Khmer Shadow Theatre to the Masterpieces of the Oral and Intangible Heritage of Humanity in 2003 and 2005, respectively.