World's Greatest: Man Made Wonders

Once powerful and populous centres of influence, these cities are now classed as ruins. All lost, one way or another, to the ravages of time. In their re-discovery, these great lost cities are providing clues to how our ancestors existed in the world. They remind us that ancient civilisations were not so far removed from our own. Machu Picchu, Petra, Bagan Tikal, Pompeii, Teotihuacan, Angkor Wat. Part 1 of 6.