Medicinal spa created with the discharge from a geothermal energy plant.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

The resting place for anonymous victims of the Danube's dark waters.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

This classic restaurant features a gorgeous mirror-clad room.

"Girl in a Wetsuit" is what happens when a sculptor has to find a way around a 100 year old copyright.

The prototype for all Nazi concentration camps.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

One of the last few places in Manhattan that employed a pneumatic systemic keeps it on display.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

Niagara Falls holds a special place in Nikola Tesla's history, so they put a statue on it.

A beloved Chicago music venue offering cold beer and lots of “Friendly."

Internationally known record store and purveyor of "dusties."

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

Louise Bourgeois' 30-foot-tall steel spider sculpture.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

Metro station with a claim to rock n' roll fame.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Art and a pun, all in one.

An old department store turned Nazi prison turned artist commune.

Blitzkrieg bop your way through Berlin's Ramones Museum.

Cold war icon and onetime "hole" in the iron curtain.