The stone platform at Khao Khian in the reservoir is a vast expanse of sandstone measuring hundreds of rai, resembling Phu Chi Fa, a well-known tourist attraction in Chiang Rai. However, this site is located in a flat area, making it ideal for conservation and archaeological tourism. The stone platform covers an area of approximately 100 rai, allowing visitors to comfortably sit, relax, or even set up tents for an overnight stay. Importantly, this location also serves as a historical learning site, as ancient rock paintings have been discovered in two shelter areas nearby. These geometric designs depict images of humans, animals, and boats, suggesting that it may have been an inhabited site for prehistoric humans. The discovered rock paintings are believed to be from the same period as the famous Phu Hi Huan cave in Ao Luek district of Krabi province, dating back around 3,000 to 5,000 years.