Architectureal fantasy quarter of Rome.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Original cabaret handbills, posters, and feline artwork are a purrfect highlight of the Museum of Montmartre.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

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

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

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

One of the oldest medical collections in Europe focusing on rare surgical instruments.

Paris' linguistic guide to the international language of, yes, love.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This massive library holds what was once the largest book collection in the world.

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

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

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A speck of nature and art in one of San Francisco’s most notorious neighborhoods.

A huge musical instrument played by the ocean.

With the touch of a button, you can read a randomly selected short story.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

One of the oldest producers of hand-folded fortune cookies still uses its original secret recipe.

Tiki luxury on Nob Hill.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

Life-sized sculpture of a blue whale made of hand-recycled plastic trash.