San Fermín Bull Racing- Pictures

The 'encierro' or The Running Of The Bulls is the single most characteristic event of the Fiesta of San Fermin. It is the event which has given the Fiesta world-wide fame and which is broadcast around the world during the fiesta in July. It is held at eight o'clock each morning from the 7th to the 14th of July inclusive. It consists largely of young men (although women may also run) who run in front of the bulls to lead them from their pen up and into the bull-ring. It usually lasts from two to three minutes - although if there are complications due to loose bulls it can last much longer.

The length of the run is some 830 metres (about half a mile) and you don't have to sign up anywhere to take part; you just enter into the run and choose the street where you will run and try to do as best as you can. The run began as part of the process of moving bulls from the edge of town to the bullring. During the mid 1800s, runners began to join the herd on their journey.
This is not the place to go into details but just to give a general outline, things happen more or less like this.
With the first rays of light of the early morning the woodenfencing which lines the route is erected. Then the night-long revellers aregradually cleared from the streets by the local police. The street-cleaners then move in to mop up the accumulated rubbish and dirt caused by the night-long revelry.