Small caves once used as a hiding place for some of those accused during the Salem Witch Trials.

This New Orleans tree is filled with hidden chimes that produce a carefully tuned melody.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

An ancient tree that was once the favorite of a young Swedish royal.

A Japanese video game arcade hides in the back of a Swedish pool hall.

This grisly exhibit houses skeletons and weapons from a devastating 14th-century clash.

Street artists transformed this abandoned industrial neighborhood into one of Europe's largest graffiti exhibitions.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Sweden's "good old days" painstakingly re-created in a model village.

A rare surviving Victorian greenhouse designed specifically to house giant water lilies.

The library's graceful rotunda is like a bibliophile's temple.

A hidden bathhouse in one of Stockholm's oldest and busiest neighborhoods is open to anyone who can find it.

Dine on food tied to Viking history and legend at this subterranean Stockholm spot.

This golden temple is surrounded by hundreds of stone tablets that comprise the "world's largest book."

Revel in the Victorian splendor of the world's oldest eating establishment inside a museum.

This coffee shop lies hidden beneath a historic church.

One of three sites in England that house the National Collection of Arms and Armour.

Artists have long been drawn to these atmospheric 12th-century ruins.

An ancient cave system in Tennessee’s Appalachian foothills converted to a 1,200-person music venue.

Established over a thousand years ago, this family-run teahouse continues to serve skewers of sweet rice cake to this day.

The former home of queer novelist Yoshiya Nobuko memorializes her contributions to modern-day manga.

A little-known caravanserai hidden among farmhouses in the Turkish countryside.

This church houses the tomb—but not the remains—of St. Nicholas, the likely progenitor to Santa Claus.