This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

An eerie, derelict amusement park in Berlin.

The most visited, and possibly most controversial, museum in Germany.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

Former hunting lodge of a duke who was an avid collector of impressionist works.

A Cuban artist reclaimed his impoverished neighborhood as a dreamy folk art kingdom.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

An otherworldly restaurant perched on the edge of a jagged cliff next to a medieval holy city.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

A wooden dock art installation on Chiloé Island taps into the island's indigenous mythology.

This odd Chilean waterfall-cano hotel must be entered via a rope bridge.

A bright little alley in La Boca is a part of tango history.

A gateway to a mysterious network of underground tunnels.

Buenos Aires' city of the dead contains some very famous remains, including Eva Perón.

A record-breaking pool that uses computers to turn ocean water into cleaner, private swimming water.

A fantastical group of cliffside stairways, bridges, and twisting paths carved out of stone provide a surreal coastal hike.

Boats must transform into railroad cars to navigate this Polish canal.

This colorful artistic feature atop a Danish art gallery allows visitors to stroll through a rainbow.

Each year melting snow turns these Austrian hiking trails into scuba zones.

A natural wonder in south Denmark.

These 18th century gardens tell a rocky story of the son of Odysseus.

A unique opportunity to stay the night in retrofitted sections of sewer pipe.

The topiary maze at the Habsburg hunting lodge.

Apartment complexes built into huge repurposed natural gas tanks.