Some call it courage, others madness.
Still others attribute it just to excessive alcohol.
Whatever their motivation, thousands of daredevils from across the globe were on the streets of Pamplona, Spain, on Sunday testing their nerve by sprinting through the city streets in front of six huge, charging bulls.
Risking injury at the horns of a frantic, three-quarter-ton creature may not sound like everyone's idea of a pleasant vacation.
Yet the legendary, centuries-old Running of the Bulls in Pamplona -- part of the annual San Fermín Festival -- has attracted more and more tourists to this small, northern Spanish city in recent years.
At 8 a.m. sharp, rockets are fired to signal the start of the Bull Run. Six fighting bulls are released from their pen. Humans and bulls then begin a mad race through the cobbled streets of Pamplona, ending up in the central bull ring.
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What's the attraction?
There's no longer a practical need to herd the bulls through the city streets to the bull ring in the center of town.
The frenetic race is maintained because it's fantastic publicity for Pamplona, as well as one of the world's most memorable tests of bravery and agility.
Amazing and scary
So, what's your chance of injury?
Not as high as the fearful-looking contest might suggest.
On the first day of this year's bull run, among the thousands of runners, only four were treated for injuries.
But maybe they're counting themselves lucky, showing off their bruises as a mark of courage.
After all, it's a sign they almost certainly weren't hiding in a doorway as the bulls thundered past.