United Kingdom's Go Below offers adventure-packed cave tours in North Wales. But what made the company world famous is the unique accommodation set 1,375 feet (419 meters) below the ground level in an abandoned Victorian slate mine. Snowdonia's disused slate (a type of rock commonly used in construction) mines are …

The salt mine in Wieliczka is a significant tourist attraction and is visited yearly by over a million people. Operation of the mine ceased in 1996, after over 750 years of continuous operation. It's one of Europe's oldest salt mines and consists of a labyrinth of tunnels of over 124 …

Deep in the beautiful Andalusian countryside, in the village called Benamaurel, there’s a rather unexpected hotel. The bird’s eye view reveals doors that seem to emerge straight out of the plant-covered hillside. Impossible? Not at all! Cuevas Helena is a holiday home ran by a Scottish couple with all rooms …