The second largest in the world, this massive underground void has its own subway.

This neon lit Georgian cave claims to hold the boulder Prometheus was chained to.

The world's largest drain sits below the city of Kasukabe, Japan.

Japanese island famous for poison gas and fluffy bunnies.

Once the most densely populated place in the world, this island is now a ghost town.

Luxury hotel turned into a refugee camp, then turned back into a luxury hotel.

The oldest continual pilgrimage site in Britain was supposedly created by a gruesome beheading.

Three bridges straddle a stream, one stacked upon the other.

This abandoned asylum in Wales might look haunted, but it's still beautiful.

A subterranean playground in an abandoned slate mine.

The decaying ruins of Wales' first asylum for the mentally ill.

Skeletons, medical artifacts, and other obscure and precious treasures all displayed in a wooden pharmacist's cabinet.

Nevada's largest cactus collection stands outside a candy mogul's small factory.

These banned cigarette vending machines now sell little pieces of pocket-sized art.

It's clear this abandoned Art Deco gem was no ordinary cleaners.

This bar named after the world's first mixed cocktail was home to one of New Orleans' most notorious politicians.

Made of giant chains and hung with shackles, this iron cross honors those unknowns who perished under American slavery.

This "second" cemetery represents New Orleans' attempt to keep cholera at bay.

Despite the ever pressing encroachment of urban sprawl this grand New Orleans manse still stands.

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

Dine amidst exotic plants at this former royal greenhouse.

A neo-Gothic mansion now houses a wunderkammer of analog tech that hits on all the senses.

An exquisite Baroque church in Vienna's old town.

Collection dedicated to funeral rites, equipment, and mourning rituals of the Viennese.