They might not be considered pretty - their faces are most often described as blending the features of a jaguar and a pug-faced baby human. But they are BIG (ranging up to around 10 feet or three metres and weighing up to 55 short tons or 50,000 kilograms). And OLD: let's take a wee journey back to 1400 - 400 BC). Not being furnished with pre-Columbian texts, who can say exactly why or how these heads, carved out of single pieces of volcanic basalt, were created. Scattered across four sites through a tight section of the Mexican Gulf, the best theory to date equates them as tributes to the tennis stars of their day. Each face has been given unique features and wears a helmet with distinctive carvings, and the Olmecs left behind Mesoamerican ballgame 'courts' - tracts of land with stone-wall sides. Forget the small furry balls of the game today. The Olmecs supposedly did it tough, bashing around a solid rubber ball weighing in at around nine pounds (four kilograms) or more. Well, that would explain their helmets.