The caves contain crystals that have formed through dripping water - these are extremely impressive formations and make the visit well worth it. The air inside the caves is at times cool, at others, extremely humid. This is not a place for the claustrophobic and you should consider the visit carefully if you have any ailments or illness.However, these precautions aside, the caves are quite safe and guides are available to guide you through the caves and steer you out of harms way (although you may have to crawl through some smaller gaps!). The two main caves (Tham Phra Nawn and Tham Seua Dao) have electric lighting and can be visited without a guide. The caves contain a number of sacred Buddha images