Collapsing castle on the Hudson river was once the storage site of military surplus business.

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

The headquarters of the Mahanikai school of Buddhism, Thailand's largest monastic order.

A battle between nature and architecture in the Cambodian jungle.

15 monolithic temples emulate an eroding sand castle.

The remains of what was, not so long ago, the world's largest city.

The largest hewn stone in history.

Mausoleum and Holy Seat of Antiochus I of Commagene.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

A mecca for India's Jains.

Underground monastery and fortress.

This hunter-gatherer architecture is believed to be the oldest religious complex known.

This complex of vertically-excavated Buddhist, Jain, and Hindu monolithic temples in India's Maharashtra providence illustrates a spirit of tolerance characteristic of ancient India.

Rock-cut cave complex filled with ancient Buddhist artwork.