Built in 1513, Wat Visoun or Wisunalat is the oldest and perhaps the most beautiful temple of Luang Prabang. The temple strikes visitors with its huge stupa called That Makmo, which in on the temple compound. Because of its odd shape, this stupa is commonly known as the watermelon (Makmo ) stupa in stead of its official name That Pathum (Lotus Stupa). The stupa originally housed many ancient Buddha images, including the Luang Prabang sacred Emerald Buddha. Many were destroyed during Chinese invasion in 1887 and a number of them are now preserved in the Royal Palace Museum.
Like most Lao wats, the Wat Visoun features multiple roof architecture. What sets it apart is its roof was embellished with two additional gable roofs and covered two side galleries. Style evokes simplicity, since the Sim does not have high gables at the top or dramatic sloping roof down to the ground, like most other Sims in Luang Prabang. Close to Wat Aham (southeast), Wat Wisunalat was probably built on the rice fields and represented the guardian spirits of the city: Pu No and Na No (Phou Nheu and Nha Nheu).