The final day of the Sanfermines running of the bulls festival saw huge beasts from an iconic ranch chase thousands of runners down the streets of Pamplona, injuring some 13 people, officials said.
The bulls from the Miura breeding ranch, whose legendary beasts inspired writer Ernest Hemingway and car-maker Ferruccio Lamborghini, thundered down the 875-meter (just over half a mile) course in two minutes and 10 seconds, making it the fastest run of the year.
The herd was densely packed and fast-moving, mowing down red and white clad participants, or "mozos," as they tried to run just ahead of the animals' potentially deadly horns.
An average of 2,000 runners take part in each of the daily runs that take place at 8 in the morning during the ancient, world-renowned fiesta that attracts many more onlookers than adrenaline-charged participants.
Some 13 festival-goers were attended for injuries at Pamplona's Navarra Hospital complex, although none were gored, the regional government said in a statement.
According to the hospital's surgery team deputy director, Jon Ariceta, among the most seriously injured was an American national identified as A.G.O., who was trampled in the tunnel that leads to the bullring that marks the end of the course.
The victim, a 30-year-old man, suffered severe head trauma, was partially scalped and received a strong blow to the back.
Another American, aged 36, suffered chest and back bruising, while two French men and an Italian were also among those who received hospital treatment.
Only one of the injured Friday was from Pamplona.
Near the end of the course, a cluster of mozos had piled onto the barricade to avoid the ornery beasts but instead were smashed into by almost the full herd.
In quick succession, two men standing a meter apart were struck on their heads by the side of a horn, narrowly avoiding being gored in the face.
They were swiftly followed by a third man who was flipped onto his back and thrown, after his trousers became caught on a horn, and was left hanging onto the animal for a few seconds.
With so many people piled up on the ground, a fourth bull had some trouble moving through and its hooves became tangled up with the mozos.
The animal most likely trampled a few participants just as they thought the worst of their ordeal was over.
Only two of the famously muscle-bound Miura bulls that ran Friday weighed less than 1,323 pounds, the regional government said in a statement.
The Miura ranch dates back to the 19th century and is famous for its large and ferocious beasts that were immortalized in Hemingway's 1932 book "Death in the Afternoon."
The brutes also inspired Lamborghini, who upon visiting a Miura ranch in 1962 decided to make a bull the emblem of his car company, later naming a luxury sports car after it.
Friday marked the final day of the Sanfermines fiesta, a nine-day event which dates back to the 14th century and sees around one million people descending on the town of Pamplona to eat, drink and watch the daily running of the bulls.
This year's edition saw some seven people gored and at least 37 others injured, of which seven remain hospitalized, not including those who were wounded on Friday.
At midnight, people will gather in front of the city hall to mark the end of the fiesta.
Revelers will carry candles and take off their red neckerchiefs as they sing "Pobre de Mi" ("Poor me"), a lament that the lively festival has come to a close until next year.