Catacombs turned marketplace.

A building so large that it has its own weather.

In this case, 'zero' marks the spot where the iconic Old Spanish Trail ends.

Trade in that pesky human soul for cold-hard circuits.

The city is full of whimsical portals to another world.

A castle built by an eccentric medieval enthusiast in rural Ohio.

The largest earthwork effigy in the world.

Once connected to the outside world by a single train track, this ghost town is looked after by the National Park Service.

The world's longest known cave system.

Visit this playground of waterfalls, caves and sinkholes.

A bizarre roadside attraction and the first instance of miniature golf in the world.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

Deep scars on the earth left by the Ice Age.

Take a drunken tour inside the world's largest known geode.

Prison made famous by The Shawshank Redemption has been out of commission since 1990.

An office built to look like a giant basket.

Beyond the usual stories that attend old prisons, this one has deep bloody undercurrents.

America's post-nuclear-attack chambers of Congress.

This rural community has attracted both scientists and techno-refugees due to its federally-mandated lack of technology.

The world's largest fully steerable radio telescope.

Two insane asylum bodies embalmed by an amateur.

A table rock formation that has been intriguing West Virginians for years.

These rows of World War II-era bunkers were the scene of some of the infamous Mothman sightings.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."