Dozens of padlock-trees along the Moscow River.

The avant-garde design was able to bypass strict Soviet regulations on architecture.

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

Moscow's imposing monument to the Space Age.

A sculpture park of the tossed aside relics of the USSR, from Stalin to a massive Soviet emblem.

Museum celebrating the achievements of the Soviet space program.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

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

Moscow's other, lesser known kremlin is a fairytale-like cultural complex modeled after Old Russia.

This platform is now a memorial dedicated to those who were deported during the Holocaust.

Tiny memorials honor individual victims of the Holocaust.

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

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

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

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

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

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Once frequented by heavyweights of the Russian arts scene, this café is stuck in the 1800s.

This effigy of Peter the Great is greatly disproportionate.

Perhaps the tiniest sculpture in Saint Petersburg is a little bronze finch inspired by a song.

A scale model of Russia so big visitors are offered binoculars to rent so they can see the whole thing.

An ever-growing literary collection housed in the apartment where the Russian author penned his final novel.

Dark, eerie exhibits make for a surreal exploration of the subconscious.