Wat Okas, also known as Wat Okas Si Bua Ban, is an ancient temple that stands alongside the history of Nakhon Phanom. It houses the revered twin Buddha images, Phra Tiw and Phra Thiam, which have been cherished by the local community for centuries. Within the temple, visitors can also admire the stunning murals that adorn its walls. Among the highlights of the temple are Phra Tiw and Phra Thiam, two identical seated Buddha statues intricately carved from teak wood. They measure 39 cm in width and 60 cm in height, and are enshrined in a beautifully constructed multi-tiered pedestal that stands in front of the principal Buddha image in the ordination hall. Phra Thiam is located to the right of the main Buddha, while Phra Tiw is on the left. These Buddha images carry a fascinating history, believed to date back to the flourishing era of the Sri Khottabura kingdom during the reign of King Sri Khottabura Luang. The king commissioned the excavation of a barge to serve as a royal vessel. After completion, the barge was moved down to the Mekong River using several small round wooden logs to assist in its transport. However, when the barge reached one of the logs, made of Tiw wood, it became stuck and could not move further, causing a considerable challenge in towing the vessel. Legends say that the Tiw wood log was a sacred tree inhabited by a deity, leading King Sri Khottabura Luang to order it be carved into the statue of Phra Tiw. On a Tuesday, during the 7th lunar month in the year of the pig (B.E. 1327), a ceremonial celebration was held to honor it as a guardian of Nakhon Sri Khottabura. Later, during the reign of King Khatiyawongsa, a fire broke out in the hall housing Phra Tiw, preventing the villagers from rescuing the statue. Fearing its destruction, the king ordered the carving of a new statue from auspicious wood, creating an image that closely resembled the original Phra Tiw. Eventually, the original statue was found in the Mekong River, prompting King Khatiyawongsa to enshrine it alongside the new statue, which was then named Phra Thiam. The murals within the ordination hall are also noteworthy, featuring beautiful wall paintings that depict various Jataka tales. The two supporting beams display images of deities and celestial beings within ornate frames, while the ceiling is painted with golden stars on a red background. Every column in the hall is adorned with vibrant, colorful patterns, making the temple a true feast for the eyes.