Depart your central Reykjavik hotel by air-conditioned minivan and travel to the volcanic Blue Mountains, home to a large lava field that covers a network of extraordinary lava tunnels and caves. On route, listen as your guide describes how these lava tubes were formed when lava solidified above ground while magna flowed and moved beneath it, eventually forming twisted corridors and chambers. On arrival at the plateau, put on your provided specialist caving equipment, including a helmet with a flashlight. Then, after a safety briefing, follow your guide into the Leiðarendi, one of the region’s best-known caves. Leiðarendi translates as ‘end-of-the-journey’ in Icelandic, and the tunnel more than befits its name — a long, pitch-dark tube that opens into wide and high hallways. With your way illuminated by your helmet torch, head through the tunnel behind your guide. Be prepared to crawl over uneven terrain along some sections as you progress. While you explore, soak in the silent and eerie beauty around you — nature at its rawest. See the beginnings of new stalactites and stalagmites, and ogle the multicolored lava formations and streams evident in the walls and ceiling as your guide explains how the different types of lava indicate different eruptions through the ages. After discovering the cave, emerge back into the daylight and change out of your caving gear. Then, relax on your minivan journey back to Reykjavik, where your trip ends at your hotel.