Hydraulic systems in an ancient underground Iranian city.

Celebrated as a center of civilization, the remains of the ancient city have been nearly destroyed by greed, egoism, and war.

9th century Abbasid mosque, damaged in modern warfare.

A complex of six forts embedded in the Rajasthan hills.

Largest sub-glacial lake ever discovered.

A lush desert oasis in the shape of a narrow crescent.

Secret Soviet city once home to Russian cosmonauts and space training facilities.

Mysterious spherical rocks in the semi-desert of western Kazakhstan.

One of the most horrible legacies of the Cold War is a site where the Soviet Union tested nuclear bombs on civilians.

Former island in the Aral Sea used to be a top-secret Russian bio-weapons facility.

An entertainment center in a huge transparent tent.

World's oldest and largest space launch facility, once a secret missile testing site.

Rusting ships sit in a desert where a sea used to be.

Home to the most complete dodo remains known - one head, and one foot.

Submerged trees jut ghost-like out of an idyllic turquoise mountain lake.