Spanish riders with lances herd fighting bulls from the ranch of Lagunajánda through the forest outside of town during the fourth 'encierro,' or bull run, in the Fiesta de Cuellar, in Castilla y Leon, Spain, 31 August 2016. The fiesta in Cuellar is recognized as one of the oldest in Spain, dating back to the thirteenth century. The bulls are herded by hundreds of horsemen through a forest and hills for 5 kilometers and then into town where runners try their luck and skill running with the bulls.