Trips which may become real inside physical replicas of the cave; maybe the only way to visit once it is no longer accessible due to the end of mining activities. Giant crystals The amazing ...

Discovered in 1999 inside an abandoned mine in Southern Spain, Pulpí Geode is the largest crystal 'cave' of its kind in the world. But what exactly is a geode and how do crystals form inside them?

15-story mixed-use tower in Denver by MAD Architects. A touch more organic in approach, it appears as though blobby stone ...