Tham Nam ถ้ำน้ำ literally means a water cave. Locals call Tham Khao Shiva ถ้ำเขาศิวะ. It is highly recommended. Amazingly, the nature offers this cave with a running stream inside throughout the year especially in rainy season there will have much more water. Walking along muddy to clear stream from knee length to cannot-reach-ground level is very adventurous and challenging in my life. Additionally, going along in a dark and moistures atmosphere is spooky, but so much fun. About safety, cave officers and local tour guides will give you special kinds of shoes, a life jacket and explain what you will see and what to do during your trek. You cannot imagine that sparkling stalagmites and stalactites catch your sight until you do not want to leave. There is water running from stalactites which seem like small strong waterfalls. The highlight one is deeper along the way. It is believed that this sacred water is given by Shiva Hindu God which is related to its name. That is why some of travellers bring bottles to fill water in to drink or take a shower for good luck. For me, I just opened my mouth and drank from that water fall. Water seems to never been run out of!