This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

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

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

Lie in a hammock where George Washington stood.

Whitewashed mosque contains the world's largest carpet.

A preposterously luxurious hotel with gold-plated iPads, Rolls Royce chauffeurs, and a staff that trains by watching "Downton Abbey."

This futuristic building is yet another architectural wonder in Dubai.

The world's largest frame offers spectacular views of the city's past and present.

On any given day this sprawling market houses literally tons of government-regulated gold, gems, and precious metals.

This vast masterpiece of Moroccan architecture spreads across 20 acres.

One of the two original gateways into the Kasbah, this gateway is a nesting site for storks.

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

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.

Crumbling necropolis set high above Fez.

The oldest known university in the world is in Fez, Morocco.

Traditional 11th-century outdoor tannery.

The courtyard of this small Marinid madrasa is a dazzling example of intricate Islamic architecture.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

This former royal palace with gorgeous gardens became the first museum in Morocco.

The largest and best-preserved Roman amphitheater in Africa was designed to seat 35,000 people.

The best-preserved Roman small town in North Africa.

Some believe this abandoned Brutalist masterpiece inspired George Lucas's Sandcrawler.

The ancient heart of Tunis is an enormous maze of narrow streets and alleyways.