Over a thousand feet beneath the Detroit streets is a subterranean metropolis few are allowed to enter.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The stunning interior of this Gothic church is covered in ornate gold details.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

The world's oldest bookshop still in operation.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

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.

You don't have to be an ambassador to dine like one.

The South African dialect's complex history is immortalized in stone, in one of the world's only monuments dedicated to a language.

A collection of human remains, animal body parts, and other macabre curiosities all legally for sale.

The history of radiation is on safe display at the foot of a radiation science laboratory.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

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

Charles Babbage's proto-computer, painstakingly brought to life.

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

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

The curios of pharmacist and collector Henry Wellcome.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

A Natural History and Science Emporium.

The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.