The largest cave in Thailand, and the fourth largest in the world, is located in Palm Phatthana sub-district, Manang district, Satun province. As you venture into the cave, you will encounter a spacious hall with towering ceilings adorned with stalactites and stalagmites, still glistening with droplets of water. When illuminated by your light, they sparkle beautifully. Additionally, certain areas of the cave's walls reveal fossilized remains of bacteria (stromatolites) and ancient marine creatures (nautiloids), indicating that the limestone in this Phu Pha Phet cave dates back to the Ordovician period, approximately 450 million years ago. Furthermore, remnants of pottery artifacts suggest that this cave once served as a dwelling for prehistoric humans.