Thousands of spectators gathered in the Tuscan town of Siena for a traditional bareback horse race around the main square. The Palio di Siena has been held in the Piazza del Campo in the centre of the medieval town, twice a year, almost without fail since 1656.

Palio di Siena
Jockeys Andrea Mari of Civetta (Owl) parish and Francesco Caria of Aquila (Eagle) parish ride, during the Palio di Siena horse race (Stefano Rellandini/Reuters)

Siena is divided into 17 contrade, or parishes, and each enters a horse and a rider in the race, although only 10 make it to the finals. The parishes all have their own banners, jockeys' colours and mascots, dating back to the Middle Ages.

The race rarely lasts longer than a few minutes, and the winner is determined by which horse -- not which rider -- crosses the finish line first. In 2010 the horse owned by the Selva (Forest) parish crossed the line without its jockey and was declared the winner.

The winning parish is presented with the Cencio or Palio, a silk banner.