Tens of thousands of revelers have packed Pamplona’s town hall square in northern Spain to celebrate the traditional firework blast that marks the start of the San Fermín bull-running festival.

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.