Twice each summer, the Italian city of Siena turns over its streets to horse racing. The event, call the Palio, dates to medieval times and once included boxing, jousting and bullfighting. Racing of buffalo, donkeys and, later, horses began after bullfights were banned in 1590.

Not only do the horses in the Palio run on the streets of the town piazza, but the riders compete bareback — no saddles. The tight turns are dangerous for both riders and horses. One horse died this year in a preliminary event when it ran into a barrier. Despite outcries that the race is an anachronism, the tradition continued Saturday.

The breakneck race once was even more dangerous. In 1729, the governor of Siena restricted the number of starters to 10, a limit that remains in place today. The horses represent various neighborhoods of the city.

The first race is held July 2 each year to coincide with the Feast of the Visitation and a local festival to celebrate the "Madonna of Provenzano," a painting purported to have curing powers. The second race each Aug. 16 comes a day after the Feast of the Assumption, dedicated to the Virgin Mary. A pageant with colorful parades and medieval costumes precedes the races.

A priest blesses the horse representing the Civetta, or Owl, neighborhood, as rider Andrea Mari holds the horse.

Perched in a balcony above the piazza, Barcelona soccer coach Josep Guardiola watches the Palio. The riders make three circuits around the piazza in the race. Several inches of dirt are poured on the city streets to give the horses some stable footing.

Rider Giovanni Atzeni celebrates after he crosses the finish line aboard Mississippi to win the Palio.

Winning rider Giovanni Atzeni celebrates his victory in the Palio. He represented the Oca, or Goose, neighborhood.

Rider Giovanni Atzeni celebrates with the crowd after winning the Palio.

After winning the Palio horse race, Giovanni Atzeni gets another ride — from the excited fans celebrating his victory for the Oca, or Goose, neighborhood of Siena.