STORY: Sporting white clothing with red neckerchiefs, hundreds of runners armed with adrenaline were chased through the narrow city-centre streets by steers and specially-bred fighting bulls to Pamplona's bullring where the 800 meter course ends.
Thursday's run lasted 2 minutes and 35 seconds.
The San Fermin festival dates back to the Middle Ages and has religious origins. Participants still chant to an image of the saint and ask for his blessing before the run.
Popularized by Ernest Hemingway's novel "The Sun Also Rises," Pamplona's fiesta attracts thousands of thrill-seekers and revellers from around the world who come to witness the morning bull runs over the week-long festival.