Favoured by 'alternative' youth on summer evenings, the Circus Maximus seen up close is a scrubby dog park littered with broken glass and cigarette butts. However, from the Palatine hill it's still possible to visualise the flat base of the long, grassy basin as the racetrack, and the sloping sides as the stadium stands, and with a lot of imagination the roar of hooves can be heard. Brick remains of the original seating at the southern end are the only visible remains of the structure (the tower there is medieval). Recent excavations have also unearthed a mithraeum from the first century BC. The oldest and largest of Rome's ancient arenas, the Circus Maximus hosted chariot races from at least the fourth century BC. It was rebuilt by Julius Caesar to hold as many as 300,000 people. Races involved up to 12 rigs of four horses each; the first charioteer to complete the seven treacherous, sabotage-ridden laps around the spina (ridge in the centre) won a hefty monetary prize and the adoration of the populace. The circus was also used for mock sea battles (with the arena flooded with millions of gallons of water), ever-popular fights with wild animals and the occasional large-scale execution. Perhaps not accidentally, the furious, competitive flow of modern traffic around the circus goes in the same direction that the ancient chariots did.