FenceIn Pamplona a set of wooden fences is erected to direct the bulls along the route and to block off side streets. A double wooden fence is used in those houses where there is enough space for it, while in other parts the buildings of the street act as barriers. The gaps in the barricades are wide enough for a human to slip through, but narrow enough to block a bull. The fence is composed of around three thousand separate pieces and while some parts are left for the duration of the fiesta others are mounted and dismounted every morning.[9] Spectators can only stand behind the second fence, whereas the space between the two fences is reserved for security and medical personnel and also to participants who need cover during the event