This ancient Irish religious site is covered in ancient carvings, many of which have barely aged.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

Once thought to be the mysterious work of a witchy prophetess, a well with unusual properties turns objects into "stone".

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

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

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

The sign at the garden gate reads: "These Plants Can Kill."

This enormous secondhand bookstore inside a Victorian train station sparked the "Keep Calm and Carry On" craze.

This century-old grotesque has a mysterious history and may not actually be a rabbit.

Stonehenge has nothing on Castlerigg’s views.

What was once England's second-richest abbey is now a haunting ruin.

Climbing to the top of the cathedral's bell tower offers sweeping views of these medieval ruins.

Nine centuries-old fortresses guard the walls of this medieval Romanian city.

This enormous abandoned prison was once dubbed the "Bastille of Romania."

This eccentric folly house was designed by Romanian thinker Bogdan-Petriceicu Hasdeu, with a helping hand from his deceased daughter's spirit.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

This snug medieval lane is one of the narrowest streets in the world.

This bone-filled cave got its name after they found 140 bear skeletons inside.

This Romanian village may have been drowned, but it is long from forgotten.

Even drowned in an ocean of toxic waste, the remnants of this Romanian village stand tall.

One of the oldest churches in Romania is believed to have been built on the site of a pagan temple.

A giant portrait of an ancient king looms over the river.

No one knows who built this strange cave of worship or exactly why.