A preposterously luxurious hotel with gold-plated iPads, Rolls Royce chauffeurs, and a staff that trains by watching "Downton Abbey."

This beautifully verdant lagoon is tucked below a massive volcano in a crater atop a black pebble beach.

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

Visit a surreal landscape so otherworldly NASA actually used it to train the Apollo 17 crew.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

Buried five stories underground, this Soviet bunker is packed with gas masks and Cold War paraphernalia.

What looks like a suicide in progress is actually a statue of Sigmund Freud.

Macabre astrological automaton clock dating to the late 1400s.

The largest stretch of the Berlin Wall is right on top of the former SS headquarters

Check the time in 145 countries at once with this East German relic.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

A restaurant and observation deck built in a unique broadcasting antenna.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

A Nesting Doll of Churches.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

The yawning maw of this pagan visage is said to bite off the hands of liars.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The biggest mirror ball in the world

A typographic tribute to the many comedic greats who make Great Britain laugh.