RUN FOR YOUR LIFE! That's what thousands of thrill-seekers are doing this week in Northern Spain for the 2012 running of the bulls at the annual San Fermin Festival.

If Pamplona, Spain, is famous for anything, it's the annual Running of the Bulls. Thousands of participants take to the street each morning of the nine-day festival to run from a pack of five charging bulls led by a guiding steer. The bulls -- which can weigh up to 600-kilograms (1320-pounds) -- chase the red and white-clothed participants through a winding 849-meter (928-yard) course to the city bullring. The whole ordeal lasts just three minutes and, at 8:00 a.m., it's the culmination of a full night of revelry.

The festival, made famous outside Spain by Ernest Hemingway's The Sun Also Rises, wraps up on Saturday. Four people -- including an American and two Britons -- were slightly injured in minor gorings in the five runs completed so far but, as of yet, there have been no deaths this year. The last fatality came in 2009 when a bull gored a 27-year-old Spaniard to death, piercing his neck, heart, and lungs in front of hordes of tourists. Fourteen others have been gored to death since records began in 1924.

Beyond the death-defying running of the bulls, the San Fermin Festival also includes fireworks, sing-alongs, street parades and bullfights, where many of the racing bulls are killed by matadors. The celebration traces its roots back to medieval times and today attracts about a half million visitors to the city of 200,000, according to Pamplona city hall, including thousands of foreign tourists from the United States, Australia and Britain.

Have a look at some of the best photos from the 2012 event:

Running of the Bulls 2012
Runners sprint alongside Fuente Ymbro fighting bulls at the entrance to the bullring during the fifth running of the bulls at the San Fermin festival in Pamplona REUTERS
Running of the Bulls 2012
A fighting bull slides towards the fence as runners sprint alongside at the Estafeta corner during the San Fermin festival in Pamplona REUTERS
Running of the Bulls 2012
A runner is tossed by a wild cow during festivities in the bullring following the fifth running of the bulls in Pamplona REUTERS
Running of the Bulls 2012
A runner is tossed by a wild cow during festivities in the bullring following the fifth running of the bulls in Pamplona REUTERS
Running of the Bulls 2012
Runners are chased by a wild cow during festivities in the bullring following the fifth running of the bulls in Pamplona REUTERS
Running of the Bulls 2012
Revellers are showered with sparks from the "Fire Bull," a man carrying a metal structure loaded with fireworks, on the fifth day of the San Fermin festival in Pamplona. REUTERS
Running of the Bulls 2012
Steers enter the bullring during the running of the bulls of the San Fermin festival in Pamplona REUTERS
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