Once a favorite playground for the world's most illustrious guests, Hotel Nacional's secret weapons and bunkers reveal a more menacing side to its golden history.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

One of Mexico's youngest major cities still holds on to this structure representing its short modern history.

A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.

Compensation for the destruction of a historic shipyard.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

There are eight natural springs around town, each with a slightly different taste.

While most of the games in this arcade take quarters, that would have been a small fortune when they were made.

America's oldest Italian restaurant is a San Francisco institution.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The longest-covered bridge in the state of Maryland.

The façade of this building looks like a bingo board, but it's really a giant clock by a famed graphic designer.

The last remnants of what was once one of the world's grandest hotels can now be found in a Manhattan subway station.

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

This small museum once served as a royal hunting pavilion for King Otto Friedrich Ludwig.

Where commuters walk through remnants of an ancient Greek necropolis.

These caves secretly held national treasures during World War II.

Legend says this sacred tree was a gift from goddess Athena.

Hoax, mistake, or evidence of dinosaurs in human times?

One of Vietnam's most iconic landmarks was built by Japanese traders and is now in danger of sinking.

The spot where the two men ate together now stands enclosed in glass.

The notorious "Hanoi Hilton" where Vietnamese colonial subjects and later American POWs, including John McCain, were imprisoned.

Monument to a brutal, ineffectual US bombing campaign and a sobering reminder of the human cost of the Vietnam War.