In this article published by Time Magazine you will get some basic information about the main festivity in Euskal Herria, the Sanfermines in Iruñea:
The Running of the Bulls
As they have each July for centuries, the narrow, cobblestone streets of Pamplona, Spain, are thundering with the sound of charging bulls. The weeklong annual celebration originated as a religious festival to honor St. Fermin, the patron saint of this small city in Spain's northern Basque region. Today the festival attracts hundreds of thousands of visitors from around the world, many of whom are drawn to its world-famous encierro, or running of the bulls, which begins July 7 and was made famous outside Spain by Ernest Hemingway's 1926 classic The Sun Also Rises.
The running of the bulls began as a way to move bulls from Pamplona's corral to its bullfighting ring. The animals would run the roughly half-mile stretch as children and adults herded them with shouts and sticks. The practice may date back as far as the 13th century, but it is known to have continued virtually uninterrupted since 1592, when the festival was moved from September to July. People are thought to have joined the herd sometime in the 1800s.
Nowadays, thousands of participants from around the world dash through Pamplona's streets trailed by charging bulls. Thousands more watch from safe nooks and balconies along the route, and spectators can also follow the events on national TV. Every morning from July 7 to 14, hordes of daredevils gather in a historic section of the city, many dressed in traditional garb and carrying rolled-up newspapers to swat the bulls if necessary. They sing a traditional homage to St. Fermin, asking him to guide them through the run. After two small rockets are fired, six bulls are released (along with a herd of steers), and the chase is on. The event generally takes just a few minutes.
As one might imagine, running with an angry, half-ton bull on your heels is not a particularly safe pastime. Since 1924, 14 people have been killed at the St. Fermin festival; the last to be fatally gored was a 22-year-old American, Matthew Tassio, in 1995. Witnesses said Tassio was knocked to the ground by a bull, then got up again and was struck by a second animal — a violation of the axiom that runners should remain on the ground if they get knocked down. Many people are injured each year, by both the animals and the crush of sprinters frantically making their way to the bullfighting arena on slippery cobblestones. Observers say foreigners — especially, for some reason, Americans — are most likely to be injured. "Americans come here with the image of The Sun Also Rises and just don't realize how dangerous it is and how easy it is to trip up," Daniel Ross, an American vice consul in Spain, told the New York Times after Tassio's accident.
Another factor fueling injuries in Pamplona is alcohol. As Hemingway chronicled, the festival is awash in wine and sangria, and runners partake copiously during long nights of partying. Participating in the run while tipsy is against the festival's rules, but violations are common. Another oft broken requirement is that all runners be at least 18 years of age. Many Spaniards were outraged to see televised images of a smiling 10-year-old boy dashing through the streets of Pamplona in 2007. The boy's mother was horrified as well; her ex-husband, who took the youngster to the festival, lost his visitation rights and was fined $200.
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