Founded in 1889 and since abandoned, Wat Tham Xieng Maen is in a 100m-deep limestone cave called Tham Sakkarin Savannakuha, a little northwest of Wat Long Khun. Many Buddha images from temples that have been torched or otherwise fallen into decay are kept here; during Bun Pi Mai Lao many local worshippers come to Wat Tham to pay homage and cleanse the images. The large stone-block entrance built around the mouth of the cave displays good relief work on stair pedestals, and is flanked by two large ruined spirit houses and a couple of plumeria (frangipani) trees. An iron gate across the cave mouth is usually locked; inquire at Wat Long Khun and someone will come and unlock the gate and guide you through the cave. It’s very long and dark, and parts of the cave floor are slippery, so it’s a good idea to go with a guide; bring a torch (flashlight).
