A windswept necropolis carved into the rocks overlooks the "most Portuguese town in Portugal."

This unassuming chapel in Portugal plays host to a ghoulish collection of bones.

An unassuming corner inside downtown Orlando's library offers a whole new world of the park and its history.

The last working windmill in Northern Ireland.

This museum houses an imposing skeleton army comprised of creatures great and small.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

A museum of magic with a Sadist past.

Indents in the pavement are all that remain from a grisly death machine in Paris.

"Portugal's Stonehenge" is made up of nut-like stones aligned with the heavens.

An abandoned mine now resembles a post-apocalyptic landscape of derelict buildings and blood-red pools of water.

This abandoned five-star hotel is now a five-star urban exploration destination.

A submerged village appears when dam levels drop.

This small chapel is built of human bones and decorated with a golden skeleton.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

Houses are tucked between, on, and underneath giant boulders.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

The photographs of "fairies" that fooled much of the world (including the creator of Sherlock Homes) were taken at this English stream.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

The remains of a majestic house that was once stood in the crosshairs of the Irish Republican Army.

A pair of mosaics marks the spot where the last accused witch of Dundee was put to death.

A bronze tribute to the wildly popular video game from the '90s.

The granddaddy of English geoglyphs dates back to the late Bronze Age.

There are hundreds of secret WWII bases hidden in British forests. Built to fight a Nazi invasion, they remained unknown for decades.