Alastair Sooke unpicks the reasons behind the dazzling revolution that gave birth to classical Greek art, asking how the Greeks got so good so quickly. He travels to the beautiful Valley of the Temples in Agrigento, and to the island of Mozia to see the astonishing charioteer found there in 1979, and marvels at the athletic bodies of the warriors dragged from the seabed - the Riace Bronzes.It was a creative explosion that covered architecture, sculpting in marble, casting in bronze, even painting on vases. Perhaps the most powerful factor was also its greatest legacy - a fascination with the naked human body.