Tens of thousands of people have flocked to the northern Spanish city of Pamplona to watch the annual bull run.
Bull running is the most famous aspect of the nine-day annual fiesta to honour San Fermin, the patron saint of Pamplona.
During the event, hundreds of people choose to run the 900-metre route alongside six half-tonne fighting bulls.
Despite the dangers, runners often drink copious quantities of alcohol through the night before joining the early-morning run.
On the first day of the bull run, at least six people were injured, four of them foreigners.
A total of 13 people have been killed since records began in 1924. The last death was in 1995.
Bull fighting and other events involving animals also form a major part of the festival, which is characterised by drinking and dancing.
But the bloody events have attracted the attention of thousands of animal rights activists, many of whom traditionally protest in the nude.
After nine days of non-stop partying, the celebrations will wind down on 14 July when the exhausted revellers end with a traditional Spanish song entitled Pobre de mi - or Poor Me.