TENS OF THOUSANDS of revellers packed the main square in Pamplona in northern Spain today to celebrate the traditional “chupinazo” firework blast that marks the start of the San Fermin bull-running festival.

Nearly everyone, including the throngs of foreign tourists who come to the event, was dressed in the traditional garb of white trousers and shirt with red sash and neckerchief.

As the rocket that starts the official party was fired, many doused each other with red or sparkling wine.

Revellers cool off with water thrown from balconies during the start of nine days of uninterrupted partying in Pamplona's famed running-of-the-bulls festival in Pamplona, Spain. Alamy Stock Photo Alamy Stock Photo

The highlight of the nine-day festival is the early morning “encierros”, or bull runs, starting tomorrow, when thousands of brave or foolhardy participants sprint to avoid six bulls charging along a winding cobblestoned route to the city’s bullring.

While gorings are not rare, many more people suffer bruising from falls as spectators watch from balconies and wooden barricades set up along the course. The spectacle is televised nationally.

The rest of each day is for eating, drinking, dancing and cultural entertainment, including bull fights where the animals that run in the morning are slain by professional matadors each afternoon.

The festival was made internationally famous by Ernest Hemingway’s classic 1926 novel The Sun Also Rises, about American bohemians living in Europe.