Pilgrimage site for star-crossed lovers.

This now-defunct synthetic fuel plant was once a major cog in the Nazi war machine.

The last fully working Victorian Turkish bath in England.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Macabre astrological automaton clock dating to the late 1400s.

This mesmerizing medieval monastery-cave complex sits thousands of feet above ground overlooking a valley.

This 13th-century monastery chiseled into the side of a mountain is equipped with a bridge that can be lifted to protect against raids.

Outstanding, eerie frescoes and decorations fill this 19th-century monastery.

A mysterious tunnel hidden in the shadows of a colorful, historic sanctuary.

Rebuilt several decades ago, its striking murals prevent it from being reconsecrated as a church.

Jesus turns into vines inside this chapel.

Honoring the famed folktale author, this California museum looks like it belongs in the Black Forest.

The freshest fish here are the ones you catch yourself.

The house of physicists Paul Ehrenfest was also a temporary dwelling and study for his good friend Albert Einstein.

Peek through a transparent pyramid and drink in the mountain made of books.

This unique sculpture proved invaluable when it saved a train from careening off the tracks.

A 'living museum' in Leiden, the oldest of its kind in the Netherlands.

This Dutch art piece became a Russian icon.

An institution that preserves the history of institutionalization.

A museum dedicated to the history of psychiatric treatment featuring a gallery of art made by patients.

A riverside park built around the ruins of a massive dam that collapsed in 1909.

This sprawling building built in 1890 was one of Minnesota’s earliest and largest mental health facilities.

The resting place of 18th century German mummies.

The site of the deadly Triangle Shirtwaist Factory Fire.