Unicorn. Goose. Shell. Tower. If you haven't been to Siena, Italy, if you aren't up on the city's 17 districts, these four are a colorful start. All of Siena's ancient neighborhoods play a role in the local horse race called the Palio and in Cosima Spender's documentary of the same name. 

Palio premiered at the Tribeca Film Festival this past April, and the twice-yearly race is around the bend: first comes Palio della Madonna di Provenzano on July 2, followed by Palio dell'Assunta on August 16.

Forget the Kentucky Derby. Held in a narrow, winding track on Siena's Piazza del Campo, the Palio excites conflict between districts and sanctions bribery as a basic strategy. Wheeling and dealing govern every clomp of the way, including the choice of jockey to represent each of the nearly dozen districts that participate on a rotating basis. Things can get brutal. Jockeys who get paid off to lose might end up black and blued by their assigned district, and at the height of the race, it's not unusual to see riders whacking one another with their clubs. If this all sounds a bit Medieval, it is. The Palio dates back to the 1400's.

Spender captures its modern pulse with the aid of Silvano "Bastiano" Vigni, winner of five bouts and the film's narrator, alongside a roundup of fellow retired jockeys who reminisce about the rough and tumble politics of the sport. Whatever their relative equestrian skills, it's hard to say which of these scrappy characters would win in a contest of abrasiveness and coglioni. Machismo oozes from each sweaty, exhilarating frame surrounding and during the famed 90-second race.

Two jockeys anchor the movie: veteran champion Gigi Bruschelli and his newest nemesis, swaggering upstart Giovanni Atzeni. How Bruschelli has won 13 races in 16 years is a marvel, but as we learn, more so for his political cunning than for his athletic prowess. With two races standing between him the world record, Bruschelli is cocked for the glory he figures he has coming to him. Young, idealistic Atzeni rides to a different tune. Though trained by Bruchelli, the wholesome Sardinian protegé embodies the hopes of a new generation. For Atzeni, it's all about the love of the game. "He brought back the romance," Spender told me several days before Palio won a Best Editing award at Tribeca. In this horse race cum metaphor for Italian politics, Atzeni is "giving hope," she said.

It wasn't until Spender and editor Valerio Bonelli started cutting the film that its essential theme became apparent. Reviewing the corruption of the master and the purity of the apprentice, the filmmakers soon teased out a story of redemption. The bravado of Bruschelli's "well-oiled machine" may have been "irresistible" to the Sienese, according to Spender, who grew up near Siena in Chianti, yet "they're all very pleased that a bit of romance has come back." And not just on the race track. Palio speaks to a larger phenomenon in today's Italy, where, as Bonelli put it, "there are a lot of older people pushing and squashing the young generation that's trying to come up." Not for nothing did the film climax with Bastiano's observation, 'Now it's time the youth woke up. They can't be content with just a few crumbs.' "