The current San Fermines can be traced back to the Middle Ages. The "Running of the Bulls", or "Encierro" as it is known in Spain, was born out of a necessity to transfer the bulls from outside the town to the bullring. The "Running of the Bulls" begins when the San Saturnino church clock strikes 8:00 am. Then two rockets are shot off announcing the exit of the bulls from their corrals.. The "encierro" usually lasts about two minutes. The entire route of the bullrun is about 790 meters long.