Ruins of a German castle on top of a towering stone pillar.

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

Residents of Berlin take their coffee and cake in one of the city’s most restful spaces: a cemetery.

When the rain falls, this drain system turns into a musical instrument.

A 12th-century fortress containing some of Berlin's oldest buildings.

Super-heavy Nazi architectural experiment.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

This "floating railway" is one of the world's oldest monorail systems.

This historic stone bridge has an entire neighborhood clinging to its sides.

A small but immensely extravagant palace built by the "Night King."

A long spiraling walkway winds through the woods, and around a copper beech tree at the center.

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

Berlin's old airport.

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.

An intricate and amazing house built by architect Karl Junker.

Floating swimming pool within a moored vessel.

This little museum is making sure that the art and history of the graffiti sticker is not scraped from history.

"The most colorful grottoes of the world.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

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

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

This recently restored crypt was once plagued by liquefying coffins and exploding caskets.

A whimsical bridge uses saxophones to pay tribute to two great men and the European Union.

This old, abandoned hotel offers magnificent views.