Locally called "Hom Jom" this natural geological occurrence from soil erosion is located about 6km from Na Noi in Nan province. It is a bit difficult to find as following Thai tradition the signs at the last few km are missing. But worth the extra 6km side-trip to see this extraordinary and intriguing moon-like landscape of eroded sand pillars and cliffs made by wind & rain. Although it is also said to be made by the sea about 10.000 - 30.000 years ago. I would go for wind & rain. For more information see Tourism Thailand and TravelFish
Although there is an information center and toilets there is no coffee shop / restaurant or shop. So take your drink and food with you (buy it in Na Noi). For more photos click on the heading of this posting.