Cuellar, Spain. The charm of the challenge among men and bulls is timeless. Still today the attraction of competition is stronger than fear. In the bulls’ square of Cuéllar, a young man faces a bull. He has no swords but only so much courage. But the bull is furious. Who will win? The essence of the running of the bulls in Cuéllar, is that the cattle is moved from the fence in the pine forest to the bulls' square of the city. This recurrence attracts many people because of the unpredictability of events. But many people are also attracted from what happens in the bulls' square, where the race ends. Here is celebrated the "Probadilla", a test of courage. Young and not young people give proof of their courage involving the bull in a dance of provocations and escapes.