text: The Running of the Bulls ( in Spanish encierro , from the verb encerrar , to lock\/shut up , to pen ) is a practice that involves running in front of a small group ( typically a dozen ) of bulls that have been let loose , on a course of a sectioned-off subset of a town 's streets .
simplified: The Running of the Bulls ( in Spanish el encierro , meaning `` the enclosing '' ) is an activity that involves running in front of bulls on a course of a sectioned-off area of a town 's streets .