An Orwellian sculpture with eyeball cameras watches passersby.

The romantic botanic tunnel feels like a well-kept secret.

A mesmerizing landscape of 18th-century cellars carved out of the land.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

Someone loved this song enough to carve all of its lyrics onto a tree trunk in a Berlin park.

After a nearly successful attempt on Hitler's life, the conspirators met their fate in the courtyard of this Berlin building.

A portable, wooden replica (minus the hyphen) of Hamburg’s iconic crooked coffee shop.

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

The non-native bovine herd was brought in to help conserve these Berlin wetlands.

This former quarry is now a picturesque gorge that hides a sunken lake.

A former squatter's paradise outside Prague.

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

Buried five stories underground, this Soviet bunker is packed with gas masks and Cold War paraphernalia.

The rusted creatures wait to be discovered in Prague's botanical garden.

A crumbling bakery where forced laborers from the nearby concentration camp toiled to feed their fellow prisoners and Nazi soldiers.

The site of a concentration camp where inmates were made to take part in one of the largest counterfeiting operations in history is now hauntingly empty.

A tilted half-timbered house from 1672 is built into a salvaged segment of a medieval wall.

Named after the German word for "a longingness to travel," this park brings together thousands of city and street signs from around the world.

The largest brick bridge in the world.

Terrifying derelict military hospital once housed a recuperating Hitler.

One of the oldest cemeteries in Germany was originally used for victims of a cholera epidemic.

This conical hill was built as a testing ground for an engineer known as the Glider King.

A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

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