When I was at school, 4 meters was about 12 feet........so a 13 ft wall would be only 1 ft higher than this. I wish somebody would save me from these " Air Heads " at the top and the TERRIFIC ideas they have. 
http://www.dailymail.co.uk/video/news/video-1208490/How-scale-wall-four-metre-wall-ease.html
