Every year, the Festival of San Fermin attracts thousands of visitors to Pamplona, Spain. Lasting nine days, the festival kicks off with massive crowds at the Chupinazo in Pamplona town square, followed by a carnival, fireworks, many bullfights, and of course, the encierro, or "running of the bulls." Held since 1591, San Fermin remains a popular, if also dangerous and controversial, event: Several people have been injured already this year, and the festival continues until July 14. Collected here are some scenes from the first days of this year's Festival of San Fermin.