A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

Cliffside houses provide a spectacular view from their perch above the valley.

At the foot of a waterfall lies a peaceful swimming lagoon and evidence of over 60,000 years of human habitation.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

A completely underwater art museum sends a stark message about humans' impact on the environment.

Considered the birthplace of the Copper Age and Bronze Age, the river is tinted red from 5,000 years of mining.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.