These little castles each held thousands of pigeons.

Putrefaction plateaus in Iran, where the dead were sent for decontamination before going to their final resting place.

The fire inside this temple has burned for more than 1,500 years.

Long before air conditioning, Persian architects found an ingenious way to cool off.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

London's smallest police station is barely the size of a phone booth.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

God's Saharan sandbox of wrath.

One of the most spectacular canyons in the world.

Vast stretch of tide-pools with a unique Moroccan charm.

Morocco's Argania trees are infested with nut-hungry goats.

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

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A museum wholly devoted to juvenescence.

Rebuilt remains of a temple to Roman god Mithras.

This 1920s Dutch barge is now a floating bookstore.

The pioneer of psychoanalysis spent the final year of his life here, still seeing patients on that famous couch.

Eighty million natural history specimens call this gargantuan museum home.

Pettah's beautiful floating market was once a stinky canal in a sketchy industrial area.

An ancient temple to the Hindu god Shiva surrounded by jaw-dropping scenery.

These "50 Fortresses" have been unearthed in the ancient oasis of Khwarezm.

Ancient barriers wrap around what was once an important stop along the Silk Road.

Bombed and burned, this monument represents the often controversial ties between Vietnam and Cambodia.