It was originally a military stronghold during the Rom Klao War period. At Pha Muak, it is a viewpoint overlooking Ban Na Pho, Ban Muang Phrae of Thai side, and Ban Mueang Phrae of Lao PDR Side (notice the Hueang River) In winter and rainy season, this is one of the most beautiful spots to see the sea of mist in Na Haeo District. From Pha Muak, we can walk along the ridge using the old soldier's path for about 900 meters, past Pha Thai Flag (where soldiers have painted the cliff with the Thai flag) and military base (with bunkers and old tools). From the bunker, we can see the top of Pha Nong which is a large sandstone. Then, we have to climb to the top of Pha Nong, and there will be an old military bunker and the swamp that the villagers blocked for consumption in Wat Pa Na Pho (Formerly, it was a natural swamp, without mortar. But, there is a story that, the water in this swamp never dries up even when it is taken out, it still not dry) In addition, at the top of Pha Nong, we can watch the sunrise and the sea of clouds at the same time