A short drive upriver from Khong Jiam, the Mekong swings around a giant meander, carving a great slice from the sandstone bedrock. Protected as the Pha Taem National Park, the resulting escarpments, capped with stands of flowering trees and weird mushroom-shaped rock formations, harbour some of the finest prehistoric rock art in Southeast Asia – a lively assortment of geometric human figures, hand prints, animals, farming and fishing scenes rendered in red ochre. The paintings are believed to be 3,000–4,000 years old.