This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

This French anatomy museum greets guests with a skinless man, mid-shovel.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

A haunting collection of the vanished and disappearing natural world.

Held in an old church, this clockwork museum maintains a special focus on titanic tower timepieces.

Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

It's always summer at the beach inside this former airship hangar.

This serene oasis in an affluent Los Angeles neighborhood holds some of Gandhi's ashes and got Elvis into Eastern Philosophy.

The world's first ice hotel is still one of the most elaborate and beautiful.

The history of German architecture is explored across this fairy-scale mini-city.

Underneath a chalk hill in France lies what Hitler hoped would be the underground launching base for a devastating new weapon.

A museum that cashes in on its infamous little people while teaching you a thing or two about the Irish fey.

Modeled after a famous church in Vienna, Austria—but in Helena, Montana.

An underground city of ancient quarry tunnels hid thousands of Allied soldiers in WWI.

This former boomtown "island" is now submerged below Folsom Lake.

Concrete crosses scattered across the Arizona scrubland which were used to align spy satellites.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.

Gladiators battle and chariots race daily in the ruins of a once-great Roman city.

This narrow path was cut right into a French mountainside to feed the country's early naval expansion.

A site where “the ravages of the war are more striking…than any other place in contemporary Spain.”

The famous boat that once ferried Bogart and Hepburn still floats in Key Largo after being abandoned for years.

This museum houses an imposing skeleton army comprised of creatures great and small.