Located some four kilometres north east of Vientiane city centre, Phra That Luang or the Great Stupa is the symbol of the Lao nation and the most important monument in the country; it appears on the national seal of Laos and various other logos of national agencies. The ground that it is built on is sacred; one legend holds that Indian King Asoka brought a breastbone of the Buddha here in 307 BCE, while another maintains that two naga once resided here. The earliest of Vientiane's three city walls is located close to the site, suggesting that it once housed the principal sanctuary of the Mon kingdom of Candapuri. Between the 11th and 13th centuries during an era of Angkorian ascendancy a Khmer temple is said to have been built on the site; this was probably in ruins by the 16th century when, after relocating his capital from Luang Prabang to Vientiane, King Sai Setthathirat I of Lane Xang chose the site for the construction of Phra That Luang and four temples, one on each side of the stupa. At the time people came from all over the country bringing jewels and other valuables to deposit in the stupa (although some only made it as far as Viengkham and decided instead to construct a stupa there - see That Mala). Today only Wat That Luang Neua (residence of the Supreme Patriarch of the Lao Buddhist Sangha) to the north and Wat That Luang Tai to the south remain. Phra That Luang was badly damaged during the Siamese invasion of 1828 and again by a lightning strike in 1896; restoration began in 1909 but major work was not undertaken until the 1930s, when in a five-year period of restoration (1930-1935) the French controversially rebuilt the monument with the main entrance facing westwards towards the city, rather than eastwards as in Buddhist tradition. Surrounded by a high-walled cloister which contains a few examples of Lao and Khmer stone sculpture, That Luang comprises three levels, each representing a different stage along the path to Buddhist enlightenment. The lowest level, a square base measuring 68 metres by 69 metres decorated with 323 ordination stones and intersected on all four sides by prayer gates, symbolises the material world of desires. The second level, measuring 48 metres by 48 metres, is decorated with 288 ordination stones and 30 miniature stupas. The central section comprises a stupa with a bowl-shaped base. Each year in November Phra That Luang hosts the Phra That Luang Festival: