Is visiting a 5,200-year-old cave system carved by white-hot magma not extreme enough for you? Then it's time to dive in and scramble your way through this 1.4 km long prehistoric subterranean labyrinth. Your expert guide will make sure your adventure is safe-yet-thrilling, so you can relax and take in those breathtaking rock formations.
This one is for the real thrill-seekers. The Raufarhólshellir is one of the largest and longest 'lava tube' cave systems in Iceland, its tunnels blasted open by the prehistoric Leitahraun eruption.
Today, it's a network of eye-popping geological formations, with thousands of technicolor stalactites and stalagmites appearing to 'drip' from the ceiling and shoot up out of the cave floor.
You'll learn all about this incredible natural phenomenon and get plenty of opportunity to admire the scenery on your underground adventure.
So strap on your helmet, grab your flashlight and follow your guide into the very heart of this natural maze.
Watch your head!
