Tens of thousands of enthusiastic participants took to the streets to celebrate the mad race through the streets of the Spanish city of Pamplona, as part of the country's San Fermin Festival. And why is the race a mad one? Well... because the runners are chased by furious bulls! The festival itself is held to honor the patron saint of the city - San Fermin.

The legendary "running of the bulls" in Pamplona is the main highlight of the nine day fiesta and sees the runners flee through the narrow cobbled streets, in a race for their very lives, avoiding the thrusts of the bulls' sharpened horns. The runners wear, traditionally, white clothes and a red kerchief, tied around their necks.

Tragically, injuries and sometimes deaths are a regular feature of this celebration and Jose Aldaba, a spokesperson for the Red Cross, was quoted in the Telegraph as saying five people were injured in this year's race. it seems one of the runners' shirt was caught on a bull's horn and he was dragged for some distance before managing to escape. Four others, meanwhile, were treated for cuts and bruises.

"Running with the bulls was the best experience I've had, so much adrenaline," Mark Martinez, a student from Los Angeles on a 10-day vacation in Spain, was quoted as saying by the Daily Mail, "I couldn't touch the horns, I might try that tomorrow."

Pamplona's famous running of the bulls' festival became popular after Ernest Hemingway's 1926 novel The Sun Also Rises. The festival itself is widely known for night-long parties, with bars allowed to remain open until 6 am (local time) and frequent announcements in Spanish, English, French and Japanese warning people not to run while drunk. A 25 year old nurse from the American state of Montana, Lindsay Erdall, described the opening party as "the craziest thing I have ever seen".

"I have been here for the setup, and now that it has started it is amazing. Not sure I will run because it is way too crowded," she told Fox News Latino. The Fox News report also added that as many as 15 people have been killed (since record-keeping began in 1924) during this event and the last such disaster happened in 2009.

The runners wait behind a line of policemen, listening for the sound of a firecracker - this indicates the bulls have been released from their holding pens. The bulls, weighing between 520kgs and 590kgs, belong to the Dolores Aguirre breeding ranch and have taken part in the San Fermin festival every year since 2002. The race, such as it is, is run through an 850m course from the pen to the city's bull ring in just two minutes and 53 seconds. Amazingly, this crazy event will run every day, until 14 July and is broadcast, the Telegraph adds, on state television.

Check out some amazing photographs of the running of the bulls festival in Pamplona, Spain, as part of the San Fermin Festival...