Whether they're equipped with claustrophobic spaces, dizzying heights or pitch blackness, adventurous hotel stays are in demand. How would you like to stay deep underground?
While planning your summer vacation, you're more likely to be on the lookout for a hotel with a pool and a panoramic view. In short, a nice place to visit with comfortable temperatures.
A small hotel in the Swedish town of Sala has none of the above - and yet it manages to draw visitors, despite year-round temperatures of 2 degrees Celsius (35.6 degrees Fahrenheit) and pitch blackness.
In the Sala Silvergruva hotel, guests sleep 155 meters (over 500 feet) below the earth in an abandoned silver mine.
The labyrinth of tunnels is enormous - altogether the pathways are a good 20 kilometers long. At one point, the mine was the largest supplier of silver in Europe. The precious metal was mined here for around 500 years.
Now the pit has become a hotel. At night, the place can, admittedly, be a bit creepy. There is no hotel personnel underground, and no other rooms or guests. Just a bed in a stone cave.
At the same time, though, it's heated to a comfortable 20 degrees Celcius. All around there is nothing but stones, a few underground lake and ponds, and every so often a quiet sigh from the rocks.
Whistling, cursing and spitting are forbidden so as not to aggravate the cave spirits - at least that's what the miners used to say, and the hotel personnel passe the tradition on to guests.
The hotel staff are situation above ground and are equipped with a radio call system, should any of the guests need anything. If anyone gets panicked, they'll still have to be patient. The elevator takes nearly five minutes to travel between the surface and the rooms below.
Click through the High Five gallery above for more unusual hotels in Europe that offer a one-of-a-kind experience within their walls.