Every year from July 7th-14th thousands pack into Pamplona to start Spain's most famous bull-running fiesta to honour Navarre capital's patron saint, San Fermin. Spain stages more than 3,000 fiestas (festivals) each year but the 7 days of bull-running are the favourite in terms of spectacle and excitement.

After the daybreak of July 7th, runners (mainly young men) gather at the bottom of Santo Domingo, which is the starting line. They crowd together and sing to the image of San Fermin which is placed in a niche on a wall. The song goes: "A San Fermín pedimos, por ser nuestro patrón, nos guíe en el encierro dándonos su bendición" ("We ask San Fermín, as our Patron, to guide us through the Bull Run and give us his blessing.")

Then, as a rocket goes off, a number of fighting bulls are let out onto the streets. A second rocket is then let off to make sure everyone knows the bulls are loose in the street. The bulls run along the narrow street 825 metres (half a mile) to a bull ring. The runners dash along in front of the bulls, aiming to feel the breath of the bull on their backs, getting as close as possible - all whilst trying to avoid getting gored by their sharp horns.

The supposed way to do this is to start off slowly when the bulls are quite a distance behind. Then as they get nearer start running like hell! You can then go near them for a short time, as near as you are prepared to risk it, and then quickly get out of the way. Runners look for a gap in the fence to slip through or jump over, or a space against the wall of the street.

When the bulls finally reach the end of the street, they go into pens and are kept until later that day they are killed in a bullfight.

The tradition is said to have come from practicality when, in 1591 residents merely had to herd the bulls to the bull-fighting arena. At first only the drovers were used to lead the bulls. But it seems that at some date, the butchers guild, who had the responsibility of buying the bulls, began to join in with the drovers and began to chase behind the bulls and heifers up to the bull-ring from Santo Domingo street - the starting point of the run.

As time passed the event became more and more popular and some people began to run in front of the bulls and not behind them, as the drovers do. In 1852, a new bull-ring was built and a new route - becoming much shorter also, because as from 1899, it was decided to bring the bulls up to a small corral in Santo Domingo street the night before they fight in the ring.

Originally only a few daring souls ran with the bulls but the adrenaline rush of running in front of a 1500lb bull has since caught on. People now journey from all around the world to run with the bulls.

Other cities in Spain also have bull running festivals if you can´t make San Fermin or don´t like crowds. Aravaca-Pozuelo, a suburb of Madrid, for example, has a bull running festival in late summer.