Reg Cox

Features seven wonders of the natural world including the Grand Canyon, the Great Barrier Reef, and Mount Everest, and shows how they were formed and why they are changing.

A look back in time to seven wonders from the medieval period ... from the Crusader castle of Krak des Chevaliers to the Aztec city of Tenochtitlan, the sites are shown as they might have been then and as they are today.