This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

One of the few working locomotive roundhouses in the United States.

A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

The only surviving prototype for Buckminster Fuller's house of the future.

One of corporate America's best-kept secrets is also one of the most publicly displayed.

Scattered around Atlanta are little doors with big charm.

Go surfing on this urban wave, "hacked" by local surfers.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

The celebrated eyesore created by starry-eyed sweethearts.

This bridge was constructed from the rubble of the infamous Bastille.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

This modest marker near Notre Dame identifies the very center of Paris.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.