Elevated freight railway turned wildly successful urban park.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

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

A crumbling hospital from the 1850s on Roosevelt Island.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

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

These unique markers designate the route American forces took during the Liberation of France.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

This ancient market is often referred to as the oldest shopping mall in the world.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

A clock set into the concrete outside a Manhattan jeweler has been telling time underfoot for over a century.

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

This lower Manhattan bar is set up in an old bank vault that rests beneath a skyscraper that hides even more historic splendor.

This castle-like building in Manhattan helped destigmatize cancer in the 19th century.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

The "Seinfeld" diner.

Visit the monolithic tomb of America's most famous general.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.