Well-signed beside Rte 3, 1.5km east of Nam Eng village, is this extensive, accessible cave system, which has a 700m section open to visitors. The main limestone formations include old stalactites encrusted with crystal deposits.
Local guides accompany visitors through the cave, but speak no English and have weak torches (flashlights). Extensive lighting is already wired up, but there are often power cuts, meaning your own torch is a handy accessory. Allow around 45 minutes for the visit.
Curious corrugations in the floor that now look like great old tree roots once formed the lips of carbonate pools like those at Turkey's Pamukkale.