The longest escalator in the Western Hemisphere takes over three minutes to ride down.

These five Art Deco homes were meant to solve the "small house problem."

Mysterious installations bring levity and light to a sometimes stodgy city.

The Conduit Road Schoolhouse is one of the last one-room schoolhouses remaining in Washington, D.C.

A building shaped like the Army Corps of Engineers logo, because why not?

This historic boathouse was constructed using salvaged lumber from burned barns.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

A terrace reminiscent of Rome's Spanish Steps is tucked away in a little park in Washington, D.C.

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

The hippo that stands on this university campus was once a drunken flea market purchase.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

This little-known national museum houses over 40,000 works of art from across the world.

An astounding collection of medical specimens, including bits of President Lincoln.

This tiny river island switches sovereignty every six months as part of a rare, centuries-old agreement.

A very uncommon water tank standing in the middle of the grapevines in Bordeaux nearly a century after its construction.

Bordered by forest on three sides and the ocean on the other, the Great Dune of Pilat is the highest sand dune in Europe.

A young Gustave Eiffel assisted in the construction of this skinny metal observation tower.

Lady Liberty's original designer installed a little clone in this French fountain.

The world's largest reflecting pool is just two centimeters deep.

The current seat of the Parliament of Andalusia was once the epicenter of the Great Plague of Seville.

A unique seaside cave where Aleister Crowley faked his own death.

Replica of mosque destroyed by Russia in the 16th century.

Russia's own leaning tower was built on a tragic historical fable.

Monastery, army base, and infamous Soviet Gulag in the far Russian north.