A perfectly preserved abandoned criminal asylum in South Australia.

A historic grist mill and active sluice on the Black River.

This huge, disused viaduct is now a crumbling concrete underworld of covered in years of graffiti.

The mortal remains of a Russian prince, priest and paranormal investigator who came to America in 1792.

An abandoned tuberculosis hospital moulders on into an uncertain future.

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

A preserved dragon's rib that remembers the legend of the founding of the city of Atessa.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

Australia's first opal field led to a mining rush in the 1890s.

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

Folklore says this medieval fortress was plopped atop a portal to hell to trap the demons below.

This unusually shaped mountaintop tower looks like a UFO floating over the city.

The largest manmade caves in Europe now function as a motorbike club's headquarters.

This fairy-tale, neo-Gothic church in the Azores is a world of magical realism.

This Canadian island is a veritable garden of decay with countless abandoned structures dotting the landscape.

An abandoned amusement park hints at the twisted history of the Newfoundland Railway.

An abandoned stretch of highway, deteriorating next to the operational one.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

Wondrous stalactites house thousands of bats in these African caves.

Largest cave system in Africa.

Caves that can't seem to quit producing the remains of prehistoric humans.

A network of hundreds of interconnected wineries in caves hides under the town center.