The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

While most of the games in this arcade take quarters, that would have been a small fortune when they were made.

The largest source of fossilized insects anywhere.

Offbeat arts organization that hosts exhibitions, events, and explorations.

A hyper-luxurious, 12,000- square foot home might be buried beneath Queens, still waiting to protect you from nuclear missiles.

Leaf through over 30,000 artists' sketchbooks in what may be the world's largest collection of doodles

This lower Manhattan bar is set up in an old bank vault that rests beneath a skyscraper that hides even more historic splendor.

Become a prohibition rebel.

A DIY art gallery/music venue/lecture hall dedicated to video game culture.

The "Seinfeld" diner.

An overgrown garden stands as a grim marker of an unrealized dream.

Railroad came. People came. Railroad left. Town died.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

A Texas-sized particle collider that was abandoned due to its Texas-sized budget.

One part local history, 99 parts gruesome haunted house.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

A hands-off space for graffiti artists to hone and display their skills.

Since 1874, this macabre collection has developed into a museum devoted to Scotland Yard's mementos of dastardly deeds.

This small town Texas cemetery is said to be the burial site of a UFO pilot who crashed in the 1800s.

A fiery crater has been burning in the Karakum Desert since 1971.