The intended purpose of this unfinished Elizabethan building remains a mystery.

Even after the church tried to wipe the practice out, this pagan festival lives on each year in a small Scottish village.

The nearly 200-year-old folly has a secret spiral staircase hidden in one of its pillars.

Grotto replete with mystical designs laid out in glued shell mosaics.

The curious and tiny collection contains some very odd objects.

The sculpture is made of more than 100,000 knives collected to raise awareness about violence.

An 18th century monument regularly tagged with unsettling graffiti referencing a 1940s unsolved murder.

A 200-year-old prison that now houses a peculiar crime museum.

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

Northern Ireland's Brobdingnagian stepping stones.

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

A roadside shrine to a late rock god only remains thanks to the unyielding efforts of his fans.

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

The anatomical-pathological collection of a man who changed surgery.

A kaleidoscopic warehouse-maze of handmade neon signs.

This South London cemetery holds the remains of more than 15,000 people.

An overgrown and largely forgotten cemetery lies hidden within the outskirts of Amsterdam.

A floating cat sanctuary on an Amsterdam canal.

Berlin's natural history museum houses the world's largest mounted dinosaur and the late beloved polar bear Knut.

An eerie, derelict amusement park in Berlin.

A museum of magic with a Sadist past.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

France's most famous cemetery, with some of its most curious tombs.