The crowd celebrates the opening of the world famous 8-day San Fermín festival in Pamplona.
San Fermín Festival
The correct outfit for San Fermín is a white shirt, white trousers and a splash of red - a neckerchief, a sash - in memory of the blood spilt by the saint himself when he was beheaded, or, some say, killed by bulls, over a thousand years ago.
What seems to be absolutely obligatory is that you drink as much as possible and what you don't drink you spray all over your friends. So bottles of cava, Spanish sparkling wine, are popular, as is a cheaper alternative called kalimotxo, a mixture of wine and Coca-Cola made to a simple recipe - buy a litre bottle of Coke, drink half and fill it up with wine.
The event was in full swing before Hemingway whetted the world's appetite by describing it in his first bestseller, "The Sun Also Rises." Later, James Michener helped things along with his book, "The Drifters."
Every morning at 8 o'clock, visitors lean out of their balconies to watch the fearless run for their lives.
With endorsements from authors like Hemingway and Michener, running with the bulls became one of the great international tests of maleness, a chance to participate in an ancient tribal rite, still surviving in the midst of modern Europe. More recently, women have been allowed to run. Whether this will eventually deal the macho tradition a mortal blow remains to be seen.
Not that I can see many women on the streets this chilly morning. The participants are almost exclusively male and range from the experts, mostly Spanish, who take it seriously and will remain as close to the bulls as possible, to the young, already drunk college kids for whom this is just another stop on the dangerous sports circuit.