London's smallest police station is barely the size of a phone booth.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This subterranean necropolis holds three floors of antler-dug grave caves.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

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

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

This modest plaza in Moneygall, Ireland has cashed in on its distant connection to the U.S. president.

Behemoth, cannon-like telescope operated by generations of Irish earls.

A contemporary art installation housed within a Gothic cathedral.

A marvel of Byzantine engineering under the streets of Istanbul.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

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

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

Norway's oldest cathedral still in use.

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

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

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

World's largest bell sits on the grounds of the Kremlin in Moscow.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

A giant white horse drawn on an English hillside may not have been intended to be a horse at all.