Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This unique building in the main square stands out among the city's typically Baroque architecture.

Overshadowed by other, more famous Maltese catacombs, this ancient burial chamber has one of the best examples of a ritual agape table.

The eclectic seaside sanctuary caters to a rather fowl crowd.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

The floor of this spectacular Baroque sanctuary is covered in memento mori.

This subterranean necropolis holds three floors of antler-dug grave caves.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

A book bound in the skin of an infamous criminal, along with countless other specimens.

The fountain marks the area where hundreds of accused witches were burned at the stake.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

The one-stop shop for all of your superhero (or evil arch-nemesis) needs.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

Skulls from the plague of 1656 and World War II bombings are united by a cult dedicated to caring for the ancient dead.

The London statue that imitates passersby.

A famous burial ground with a history both grim and literary.

Following the trail of an old metro line, this scenic path is haunted by a creepy spriggan statue.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

This hidden rooftop garden in downtown London offers a quiet respite from a bustling city.