Bulls charge through Pamplona's controversial festival: See the dramatic images

On Saturday, Spain kicked off one of its most controversial and adrenaline-fueled traditions: the Pamplona bull run.

Held every year from July 6 to 14 during the nine-day San Fermin Festival, the event brings over a million thrill-seekers and spectators from across the globe to the city of Pamplona to watch hundreds of brave volunteers get chased through the streets by six large bulls.

Every morning during the festival, at the stroke of 8 a.m., the bulls are released from their corral and charge through the narrow alleys toward the Plaza de Toros, the city's bullring, where they will later be killed by matadors during the evening's bullfights.

The runs last roughly three and a half minutes each day. For participants, mostly young men, it’s a race against time — and horns.

Immortalized in Ernest Hemingway's 1926 debut novel, The Sun Also Rises, the bull runs are dedicated to the city's patron saint, San Fermin, and date back to the end of the 16th century, according to Time. Still, the excitement doesn't come without perils.

Dozens of runners are injured every year, with a reported 16 deaths since 1924. On the first day of the festival this year, six people were injured, including a 54-year-old American from New York, highlighting the event's inherent risks, with two more injured on Tuesday. Despite the danger, the event's allure remains undiminished, drawing participants year after year despite the controversy it stirs among animal rights groups.

Here are some of the tense moments captured on camera during this year’s running of the bulls in Pamplona.