Adjacent to the bot of Wat Phrathat Doi Tung in Chiang Rai, is a mysterious deep hole in the ground, that today is surrounded by northern-style banners, called tung (fig.), and guarded by two thevada. The temple was reportedly built in 911 AD by Phra Chao Achutarat, who ordered a giant flag to be flown, in order to demarcate the site.

According to legend, the hole was used to erect the giant flag pole to which an allegedly 1,000 wah long tung was attached.