Caves have been explored out of necessity , out of curiosity or for mystical reasons for thousands of years Caving — also known as spelunking, when referring to amateurs without the proper knowledge, or training — is the recreational sport of exploring caves. In contrast, speleology is the scientific study of caves and the cave environment The challenges of the sport depend on the cave being visited, but often include the negotiation of pitches, squeezes, and water though actual cave diving is a separate sub-specialty undertaken only by very few cavers. Climbing or crawling is often necessary, and ropes are used extensively for safety of the negotiation of particularly steep or slippery passages. However, only in the last century or two has the activity developed into a sophisticated, athletic pastime.It has recently come to be known as an "extreme sport" by some