Roman ruins top white travertine terraces formed by ancient hot springs.

A marvel of Byzantine engineering under the streets of Istanbul.

The only castle in North America to ever house European sovereigns.

A crumbling cathedral condemned by an earthquake.

Every equinox this Maya pyramid puts on a spooky ancient light show.

A Mayan village preserved for centuries in volcanic ash.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

On the outskirts of a desert trading village high on the Andean plain, steel giants have been destroyed by salt winds.

A seemingly endless landscape of pure salt stretches far across Bolivia.

A valley of unique erosion patterns lends to a view like nothing on Earth.

An art museum with an eclectic design and a scandalous past.

A 125-meter long "tribute to the Brazilian people."

A historical convent known for taking in bad luck babies left on its doorstep is now an upscale shopping center.

A Buddhist theme park brings you a Buddhist version of Hell.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

For centuries young Thai men used this Giant Swing as a slingshot to heaven.

At 207 feet, one of the world's longest continuous escalators.

Home to items never before seen by the public.

Peace Park and the Atomic Bomb Dome.

This Japanese national treasure was originally built in 593.

1,001 carved statues of the Buddhist God of Mercy, each with a unique face.

This massive wooden building contains a giant Buddha, healing pillars, and tame deer wandering the grounds.

The Hanshin Expressway goes right through its 5th, 6th, and 7th floors.

An ancient capital city that dates back 3,000 years and harbors many surprises.