An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

The famous artist couple lived and worked here, in two different houses separated by a bridge.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

A church dedicated to the Mexican skeleton saint.

High atop a Mexican rainforest mountain, this ancient pyramid once drew pilgrims countries away.

66,000 pieces of art, donated by one of the world's richest men.

Superstitious? Discover the witchy side of Mexico through its largest esoteric market.

A gargantuan crystal kingdom.

An Aztec snake god has taken the material form of an apartment complex.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

Extraordinary sculpture garden created by an eccentric English poet.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

Looming communist pillar with a Czech twist.

Street artists transformed an abandoned air vent into the beloved Star Wars robot.

Dine amidst exotic plants at this former royal greenhouse.

Once the home of a hermetic monk, this cave now houses a small church.

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

There just so happens to be a court even higher than the U.S Supreme Court: a basketball court in the building itself.

Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

A promising candidate for the lost rock laid by George Washington was unearthed, but the hunt is still on.

Before Nixon, "watergate" meant canals.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.