Thousands of revelers sprayed each other with sparkling wine as firecrackers rockets exploded at noon Friday in this northeastern city to start Spain's most famous fiesta, the San Fermin bull-running festival.
"Men and women of Pamplona, Viva San Fermin!" Pamplona mayor Yolanda Barcina shouted from the city hall balcony. Below, crowds packed the town-hall square, most dressed in white shirts and trousers and donning red handkerchiefs, the traditional garb of the festival.
The "chupinazo" firecracker at midday officially starts the nine-day fiesta which was popularized internationally by Ernest Hemingway's 1926 novel "The Sun Also Rises" and centers round the daily running of the bulls.
The first bull run takes place Saturday and the spectacle, repeated each day until July 14, is broadcast live on Spanish television.
Many of the revelers had spent the night out drinking and partying prior to the 'chupinazo.'
Thuy Trinh, 28, a nondrinker from London, might have been the only sober person among the throngs.
"It's a bit crazy, but I love seeing people enjoying themselves," she said.
"Los San Fermines," held since 1591, attracts tens of thousands of people from across Europe and as far away as Australia and the United States.
Sara Newey, 23, and Rene Armstrong, 25, from Perth, Australia, recounted everything they had to drink in the past twelve hours: a bottle of Jack Daniels, several bottles of sangria, six beers each.
"You just have to keep going," Newey said with a carton of sangria in one hand and a bottle of sparkling wine in the other. They came on a tour with 600 other Australians.
In the runs, held at 8 a.m. (0600 GMT) each morning, people test their mettle and stamina by racing with six bulls along a 800-meter (875-yard) route from a corral to the city bullring. The bulls are fought by professional bullfighters each afternoon.
Since records began in 1924, 13 people have been killed in the runs. The last fatality, a 22-year-old American, was gored to death in 1995.
On Thursday, hundreds of members of the People for the Ethical Treatment of Animals, a U.S-based international animal rights group, staged a near-naked protest march in the city using slogans such as "Torture isn't culture," and "Bulls yes! Bullfighters no!"