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

The central mosque of this Mali town is entirely built from mud.

Napoleon’s home in exile, decorated with poisonous wallpaper.

A Gothic cathedral created from volcanic rocks.

The oldest inn in England served brew to the crusaders.

A pub that is literally in the middle of nowhere, but continues to do business.

The world's most remote permanent settlement on an active volcano.

A historic hotel on the edge of the Australian outback.

The cafe that acts as the social hub for the small volcanic island of HMS Bounty fame.

For over 80 years, Mayan ruins stood proudly in a most unlikely location.

Superstitious? Discover the witchy side of Mexico through its largest esoteric market.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

Interactive modern and vintage submarine equipment, World War II relics, and submarine attire.

Largest cave system in Africa.

An abandoned castle owned and ignored by Masons carries a cursed history.

Where an entire elephant skeleton, a snakeskin table runner, and thousands of animal remains become art.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

The world's largest collection of witchcraft regalia.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

Millions of glowing microscopic organisms light up the waters of this luminous lagoon.

Plundered and left asunder by grave robbers, this ancient necropolis has been painstakingly pieced back together.

An ethereal glowing blue ocean cave in Croatia.

These azure waters were thought to lead to the Mayan Underworld.

The site of many battles and tragedies, including the 40 maidens who leapt into the sea.