Several thousand thrill-seekers tested their bravery Sunday by dashing alongside six fighting bulls through the streets of the northern Spanish city of Pamplona on the first day of the running of the bulls.
Despite a large crowd of participants on Sunday because the run coincided with a weekend, only four people were treated for injuries and no one was gored, officials said.
The regional government of Navarra, which is responsible for organising the annual San Fermin festival, said in a statement that none of the four are seriously injured.
A 24-year-old Australian, identified only by the initials JC, was being treated for bruising, as was a 44-year-old British national. An American citizen identified only as CS was also receiving treatment for a minor injury.
A 36-year-old native of Pamplona with a minor injury was the only remaining in the hospital by mid-afternoon, the government said.
There was a moment of tension as the last bull of the pack became disoriented and turned around to look back at runners, but it eventually entered the bullring without charging at anyone.
The nine-day fiesta was immortalised in Ernest Hemingway's 1926 novel "The Sun Also Rises".
"It's tremendous how many people there are here today," said Enrique Maya, mayor of Pamplona.
Every morning of the festival at 8 am, six bulls specifically bred for fighting race through the narrow, medieval streets of Pamplona accompanied by an equal number of large steers - each wearing a clanking cowbell - tasked with keeping the pack tight and galloping at an even pace.
"It was amazing, phenomenal and scary, all at the same time," said William Schulz, 34, a bartender in Nashville, Tennessee.
The run covers 850-meters from a holding pen on the edge of town to the central bull ring where the large animals face matadors and almost certain death in afternoon bullfights.
The bulls used in the centuries-old fiesta can weigh up to at 625 kg. Bulls have killed 15 people since record-keeping began in 1924.
"The first feeling while you're running is just surviving," said Rick Museca, 46, a wine importer from Miami. "I feel very fortunate that the people of Pamplona should share all this with us."
Museca said he formed part of a Miami-based group of runners called Amigos de Pamplona, originally founded in 1983.
Due to the disorientation of the last bull, Sunday's run took four minutes and six seconds, a relatively long time. Every time the bull turned his head, runners scattered, tripped and fell as they tried to get away despite being hemmed in by the narrow streets.