A university observatory dome painted to resemble the beloved 'Star Wars' droid.

A former ironworks that was the first UNESCO industrial site.

This museum tells the story of lake dwellers from 4000 BC to 850 BC, replete with stilt houses and goats.

Aged nearly 1,700 years, the world's oldest bottle of wine is probably still drinkable.

Sitting in the basement of a castle, the largest wine barrel in the world is bigger than most apartments.

Home of the largest single-phase AC generator in the world.

A towering monument to war, located on a beautifully peaceful hill.

This monument to those fallen in the World Wars is accompanied by a U-boat that Germany bought for a Deutsche Mark.

A tiny island is connected to the mainland by a private railway that residents travel in their own personal wagons.

This decommissioned nuclear power plant offers tours of its Communist-era control room and reactor hall.

This classic restaurant features a gorgeous mirror-clad room.

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

This concrete residential area doubles as an open-air gallery.

Berlin's natural history museum houses the world's largest mounted dinosaur and the late beloved polar bear Knut.

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

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."

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

A two-way chairlift system between Zugliget and the highest point in the city.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

This hidden art nouveau gem was designed by an architect in search of a national style.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.