For decades, it has disappeared and reappeared as water levels rise and fall.

An extraordinary collection of vampire-themed antiques lurks on the second floor of a store.

A tradition unlike any other, this marks the site of the annual Groundhog's Day tradition.

A daily replay of the experiment that proved the rotation of the Earth.

The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

This icon of the Atomic Age now lays dormant.

Pennsylvanian mass grave and possibly mass murder.

The only geyser in the state of Pennsylvania is caused by pressure from an abandoned coal mine outside of the ghost town Centralia.

Pennsylvania's own Roswell-style UFO mystery.

A macabre farm reserved part of its 222-acres for dead bodies, all in the name of science.

The headquarters of the Fraternitas Rosae Crucis, complete with Rosicrucian pyramids, all in the Pennsylvania woods.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

This meticulously extracted nervous system allegedly came from a 19th-century custodian who donated her body to science.

A toxic ghost town sitting atop a massive coal fire.

Mutant vegetables, transgenic mosquitos, and atomic rodents span the walls of this one-of-a-kind museum.

A beautiful oddities shop crammed with strange and morbid curiosities.

House of vintage taxidermy and Steampunk sculptures in a quiet Pittsburgh neighborhood.

Though tiki culture has gone in and out of fashion, the Tonga Hut has always been flying the flag in Los Angeles.

The quiet canyon has a tumultuous history involving a doomsday cult.

This brightly made over hotel hides decades of suicide, serial killers, and mysterious deaths.

A poignant museum dedicated to the history of the Dutch resistance against Nazi occupation

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.