Scattered throughout London are ancient remnants of the city's former bounding wall.

This 1920s Amsterdam neighborhood was built as a giant experiment in concrete construction.

There aren't too many operational funiculars around, but Pittsburgh has two!

Elevated freight railway turned wildly successful urban park.

The quintessential Japanese rock garden has existed for more than 500 years.

Bangkok celebrated its shifting monarchy with a militaristic homage to democracy.

A condom-covered Thai restaurant that is more concerned with birth control than food.

Traditional 11th-century outdoor tannery.

This dramatic rail curve was once the target of a failed Nazi attack.

Ride the subways of yesteryear.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

The celebrated eyesore created by starry-eyed sweethearts.

The curious underground history of keeping Paris clean.

Meet your friends, marry your true love, or tell your enemies to kiss your butt under this historic Pittsburgh timepiece.

A restored Pittsburgh house of God has been converted to a marvelous house of suds.

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

Once the most painted on object in the world, this short campus fence is well on its way to being so again.

At 207 feet, one of the world's longest continuous escalators.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

Steepest flood safety railway in the entire world.

A portion of the old Pirates stadium over which a defining home run once flew still stands even after the rest of the stadium was torn down.

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

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