This California estate was either haunted by ghosts or the Marx brothers.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

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

France's most famous cemetery, with some of its most curious tombs.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

A bizarre house filled with an astounding array of collections.

The legendary building that needed ghostly approval before being built.

High on a hill overlooking Los Angeles lives a world famous, high power conical Tesla Coil.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

A layered tribute to the work of mosaicist Isaiah Zagar.

Try not to get slimed in Tribeca.

The fairy tale castle of the "fairy-tale king."

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

The often-overlooked ruins of one of the first buildings designed by famous landscape architect Frederick Olmsted.

A morbid secret lies hidden within the beautiful walls of the Boston Athenaeum.

A beautiful Victorian-era cemetery, complete with a miniature village.

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

An enormous, inside-out glass globe built in 1935.

A terrific purveyor of natural history objects and curios.

An emerald-green grotto just a short trip from Austin.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.