A salty cave excavated by elephants and the location of a deadly disease vector.

Human ancestor’s 3.6 million year-old footprints.

Abandoned city hidden from the world by tropical forest and isolation on the coast of Kenya.

The ancient tomb acts as a calendar that keeps perfect time.

Mile-long cave system near Great Smoky Mountains.

Mysterious ancient boulder carved with petroglyphs in the mountains of Western North Carolina.

Local history museum with mammoth bones and an old myth about local giants

This hunter-gatherer architecture is believed to be the oldest religious complex known.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

The inspiration for H.P. Lovecraft's horror stories and Batman's Arkham Asylum is now a condominium complex.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

A museum designed by and dedicated to P.T. Barnum in the town where he is buried.

Limestone caves in the Cambodian countryside, once the site of genocide, now a place of peaceful beauty.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

Museum celebrating the achievements of the Soviet space program.

A gruesome memorial for those lost in this area during the Khmer Rouge genocide.

The ruins of an ancient island city built atop a coral reef in the South Pacific are spectacular and strange enough to have inspired H.P. Lovecraft.

Every equinox this Maya pyramid puts on a spooky ancient light show.

The enigmatic and seldom visited ruins of a Mayan city-state.

The one-time stronghold of the noble Douglas family, now home to ghost sightings and nesting birds.