One of only two commuter aerial tramways in the United States.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Elevated freight railway turned wildly successful urban park.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

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

The world's first motorway was used as a racetrack until the late 1990s.

A plaque on the side of a building is a small tribute to the woman who invented an iconic Berlin fast food.

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

You've probably seen these distinctive orange-tiled columns on the big screen.

This monumental work of art symbolizes the coming together of a previously divided city.

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

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.

Berlin's beloved bear is immortalized at the Museum für Naturkunde.

Metro station with a claim to rock n' roll fame.

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

One of the world's heaviest musical instruments towers within a popular urban park.

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

Tiny memorials honor individual victims of the Holocaust.

A traditional U-Bahn station in Berlin gets a string of rather untraditional benches.

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

This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

These former Nazi anti-aircraft towers offer a singular view of the north of Berlin in the summer, and a sanctuary for bats in winter.

Berlin's old airport.

A unique Holocaust memorial tells the personal stories of the Jewish residents exiled from greater Berlin.