That Dam, also known as the Black Stupa, is a 16th-century Buddhist stupa located on a tranquil roundabout in central Vientiane, near Talat Sao (the morning market) and the American Embassy. According to local legend, the stupa was once protected by a seven-headed water serpent, or Naga, and was covered in pure gold. However, during the Siamese-Laotian War in the late 1820s, the gold was looted and taken to Siam (modern-day Thailand), leaving behind the dark, weathered structure seen today.

Despite its modest appearance, That Dam holds great cultural significance as the guardian spirit of Vientiane, blending legend, folklore, and history. Its untouched, timeworn look offers a refreshing contrast to the extensively refurbished stupas and temples commonly found in nearby countries like Thailand.