Friday, April 17, 2009 at 9:30 p.m. on KPBS TV. The achievements of the country's golden age, including how India discovered zero, calculated the circumference of the Earth and wrote the world's first sex guide, the Kama Sutra. In the south, the giant temple of Tanjore built by emperor Rajaraja Chola and traditional bronze casters, working as their ancestors did 1,000 years ago are shown. Michael Wood calls Tamil Nadu, "The only surviving 'Classical Civilization' in the world.