This vast masterpiece of Moroccan architecture spreads across 20 acres.

Deliberately hidden for centuries, the magnificent Saadian Tombs were eventually uncovered in 1917.

The largest madrasa in Morocco once housed more than 900 students within its exquisite walls.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

Like Mardi Gras, only everyone's a pirate.

California's own majestic geyser is powered by a subterranean volcano.

The romance of early commercial flight still fills this Art Deco destination.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

The only labyrinth within the city of Alexandria.

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

Long buried under the 20th-century landscape, this lift lock of the Alexandria Canal is the lone remnant of an ambitious early American transportation project.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

This statue of one of baseball’s greatest pitchers looks like something out of a sci-fi horror movie.

Through the decades, Black music stars have performed at this historic hub for music and the arts.

Look closely and you’ll notice that the color changes a third of the way up the tower.

The discovery site of the "Capitalsaurus," the official dinosaur of Washington, D.C.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.