Because some youths threw rocks and broke the window of a caboose on a passing train, an investigation resulted in the discovery of a carefully camouflaged cave near the railroad tracks in the ...

With over 8,000 cubic meters of water, it contains more 3.5 Olympic swimming pools of water volume, all geothermally heated.

Carved into the rock beneath a Swedish city, a huge man-made cave system dating back to the Cold War is being used to heat local housing. DW found out how it works ...