Pha That Luang is a large, gold-covered Buddhist stupa in the centre of the city of Vientiane, capital of Laos. Since its initial establishment, suggested to be in the 3rd century AD, the stupa has undergone several reconstructions, as recently as the 1930s, due to foreign invasions of the area. It is generally regarded as the most important national monumeā¦Pha That Luang is a large, gold-covered Buddhist stupa in the centre of the city of Vientiane, capital of Laos. Since its initial establishment, suggested to be in the 3rd century AD, the stupa has undergone several reconstructions, as recently as the 1930s, due to foreign invasions of the area. It is generally regarded as the most important national monument in Laos as well as a national symbol.