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

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

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

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.

A church of bones, decorated with 40,000 human skeletons.

An enormous and lavish Gothic church in Czechia.

This demon atop the Notre-Dame de Paris looks utterly bored.

The celebrated eyesore created by starry-eyed sweethearts.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This former asylum for Black Americans is haunted by its history of violence and racism.

Eighteen miniature death-scene dioramas.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

The trials and tribulations of marking Poe's grave.

It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."

It was once the base for a series of domestic terror attacks.

This fertility idol of questionable authenticity inspired an iconic Indiana Jones artifact.

Through the decades, Black music stars have performed at this historic hub for music and the arts.