Phu Hin Bun NPA & Tham Kong Lor

Phu Hin Bun NPA (ປ່າສະຫງວນແຫ່ງຊາດພູຫີນປູນ) is a huge (1580 sq km) wilderness area of turquoise streams, monsoon forests and striking karst topography across central Khammuan. It was made a protected area in 1993 and it's no overstatement to say this is some of the most breathtaking country in the region. Exploring the NPA on foot or by boat, it's hard not to feel awestruck by the very scale of the limestone cliffs that rise almost vertically for hundreds of metres into the sky. Arguably the highlight of the NPA is Tham Kong Lor, a 7.5km river passing through the cathedral-high limestone cave.