Made internationally famous in Ernest Hemingway’s 1926 debut novel, The Sun Also Rises, the bull runs are dedicated to the city’s patron saint, San Fermín. The tradition dates back to the 16th century when cattle herders used the bull run route to transport animals from the countryside into the city for bullfights, according to Time magazine.

PAMPLONA, Spain (AP) — Thousands of daredevils ran, skidded and tumbled out of the way of a stampeding group of bulls at the opening run of the San Fermín festival Monday. It was the first of nine morning runs or “encierros” during the famous celebrations held in the northern Spanish city of Pamplona.