High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

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

For patriotic Russians, this memorial honoring the Soviet soldiers who died liberating Berlin in 1945 is the most sacred location outside of Russia.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

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

Germany's Glienicke Bridge has a shady history of clandestine meetings, espionage, and spycraft.

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

The last remnants of a massive medieval wall that once encompassed the city of Berlin.

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

The walls of Germany's Parliament still show the scars of the Red Army takeover in World War II.

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

Learn about Iceland's hidden folk at this school dedicated to the study of elves.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

This is the oldest Roman-made bridge in the city still existing in its original state.

This ancient market is often referred to as the oldest shopping mall in the world.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

Rome’s legendary peephole vista is also a former Crusader stronghold.

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