Every town in Spain has a patron saint. For Madrid it is San Isidro. The feast of the saint is celebrated with a feria in his honor. It might involve a parade, a holy ritual as the penance of Santa Semana in Sevilla, a pagan act like burning the Fallas in Valencia or something else, but it always involves a corrida.
Papa Hemingway followed the bulls in the summer of 1931 and his experiences are the basis for "Death in the Afternoon"--a non-fiction description of bull-fighting. His summer was fictionalized in his first best-seller, "The Sun Also Rises." Today, kids in school are more likely to be tasked with reading Maya Angelou than Hemingway. We don't want them to become inadvertently masculine.
For those outside of Spain, probably the most famous aspect of bull-fighting is the running of the bulls in Pamplona. It is called an encierro.
A traditional corrida involves six bulls and three matadors who kill two each. The fighting bull is, by regulation, four years old and should have been raised in a ganaderia where he has never seen a man on foot. When the bulls arrive, usually by truck, in the town of their corrida they are corralled often at a place away from the Plaza de Toros. On the morning of the event, they are moved to the bull-ring and it often involves blocking off the streets and driving them through the lanes accompanied by a half dozen docile steers. The steers serve to keep them herded where the fighting bull is less likely to become aggressive.
The event is triggered with a cannon shot or fireworks rocket in Pamplona. Hemingway and others leaped the barricades and ran ahead of the bulls to demonstrate their courage (and probable degree of drunkeness.) Today, like much of our lives, the event has grown to excess.
Crowds fill the streets, people stumble and expensive fighting bulls are often damaged and rendered unsuitable for the ring in the afternoon. The tradition has grown to include an opening of the gates of the Plaza de Toros and of the barrera to allow runners into the ring itself. There they torment the bulls and steers and do yet more damage.
Another Feria de San Fermin has begun: