temples in Luang Prabang, and was the seat of the Kingdom of Lan Xang from 1353-1560 and the Kingdom of Luang Prabang from 1707-1946. The stupa That Luang and the Plain of Jars in Xieng Khouang were both nominated for UNESCO status in 1992. That Luang was nominated for its religious significance as a site of Buddhist pilgrimage and the Plain of Jars for its importance as a major archaeological site of Iron Age culture in Southeast Asia. Music and performance arts The national music of Laos is the lam, where a singer (songs by expert singers are mor lam) uses improvised poetry set to quick tempo music around themes of love, difficulty, and poverty using turns of phrases and subtle humor. Lam is highly regional, and many listeners can determine the setting and themes in the first few lines. A popular form of lam is basically a battle-of-the-sexes between an expert male and expert female singer to entertain the audience and trip the opposing singer up using humor, innuendo or stylistic flair. Lam can also be used in story telling as a sung form of folk poetry, and forms the oral tradition predating the national epics in literature. Lam used in animist traditions creates a type of chant which is used during ceremonies like the baci. The most integral instrument for Lao music is the khaen a free-reed mouth organ made of bamboo. Variations on the khaen are found among most ethnic groups in Laos. Laos also uses a number of classical court instruments which show strong influence from China, Cambodia and Thailand. The ensembles include flutes, zithers, gongs, drums, fiddles, lutes, cymbals and xylophones. Modern mor lam also includes electric guitars, synthesizers and electric keyboards. Theater All traditional theater in Laos is essentially musical in nature. Court music and performances known as khon and lakhon feature the most elaborate costuming and dance. Khon and lakhon originated from the Khmer court and spread throughout the region, beginning in Laos during the Lan Xang era. Typical performances included jataka tales, with the performances of the Pra Lak Pra Lam during Lao New Year in Luang Prabang being the most recognizable today. The nineteenth century spurred the creation of lam luang or Lao opera. Lam luang is a more theatrical version of lam music complete with sets, costumes and orchestral accompaniment. In 1972 the Pathet Lao formed the Central Lao Opera,