A medieval church built into an ancient cave.

The recovered bones of martyrs slaughtered during The Terror are on display in this church crypt.

An ancient artistic garden parlor full of hidden water wonders.

An unsettling painting of three faceless sisters that is surrounded by history and legend.

In 1830, cemetery workers in Cham unearthed a chamber housing thousands of skeletal remains from the 13th century, which can still be viewed today.

Ride a boat through this magnificent underground world, which now doubles as a theater.

Andrew Carnegie funded the building of almost 3,000 libraries across the world, this was the first.

A hidden tunnel leads to a medieval queen's shrine buried beneath a parking lot.

Contrary to its heavenly name, this tranquil oasis has a dark and tragic history buried with it (quite literally).

A statue of a mischievous raccoon towers over this city park.

This temple is steeped in local folklore involving a teakettle and a raccoon dog.

The cutest shrine in Kyoto is dedicated to bunnies.

Be a ninja - or just act like one.

Crawl through the hole in the middle of this stone to break off a bad relationship or initiate a good one.

A Japanese cat island also populated by the descendants of a band of banished samurai.

Built to be the ideal penitentiary, this abandoned panopticon saw several revolts and even a prisoners' coup.

Man-made cave with enigmatic carvings, some say made by the Knights Templar themselves.

Preserving the research tools, unexpected inventions, and odd collections of generations of college professors.

This curious Tudor-era castle was once home to Napoleon's greatest adversary, the Duke of Wellington.

This pyramid is dedicated to all those who suffered martyrdom for civil and religious liberty in Scotland.

A woodland close to England's "most haunted village" has been the site of many unexplained events and deaths.

Ward off bad luck and fill your bottle with "the most watery water" at this little roadside shrine in Yonezawa.

Jesus turns into vines inside this chapel.

This mansion oasis contains gardens, sculptures, and fountains just off the busy Plaça Kennedy in Sant Gervasi.