This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

A rotting tree in the middle of Seattle doubles as an elaborately-controlled art piece.

A museum dedicated to the history and exploration of both popular music and science fiction.

A saintly relic hidden in a Prague church basement.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Macabre astrological automaton clock dating to the late 1400s.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

The topiary maze at the Habsburg hunting lodge.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

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

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

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

A jaw-dropping brutalist space church seems to have crash-landed in the middle of America.