Further afield is Tham Pha Chan, with an entrance 60m high and about 100m wide. A stream runs about 600m through a limestone karst and in the dry season it's possible to walk to the far side. At its western end there is a sandalwood Buddha image in a crevice about 15m above the ground, hence the cave's name, meaning Sandalwood Buddha Cave.
Not far from Tham Pha Chan is the Nam Don Resurgence (ຂຸນນ້ຳໂດມ), a cave where the Nam Don emerges from the ground. It's quite a physical marvel to see the water coming up and out from the cave, and the lagoon that sits at the bottom of the tall limestone karst is a beautiful swimming spot.
Unfortunately, both are accessed via a rough road that runs 9km north from about 10km east of the junction with Rte 13. Go by motorbike, tuk-tuk or arrange an English-speaking guide through Tha Khaek's Tourist Information Centre.
