Waiting in the Blue Mountains between Pingvellir and Laugarvatn, east of Reykjavik, is an underground adventure. If you like a challenge than caving will be your kind of sport. Once the innate fears of darkness and small spaces have been overcome, prepare yourself for a fascinating journey. Below the ice and rock you will discover rock formations from past volcanic activity. In the coldest months there are also intricately shaped icicles to negotiate. Just to see the light of day again you will have to crawl, walk and climb your way through caves and tunnels..