That's quite an old trick of Chris Angels, I know, I used to do a bit of street magic myself. Chris Angel is an amazing street magician, and he certainly leaves his audiences in shock. Unfortunately I have no idea how he manages to pull this trick off, but it can't be easy, of course he's not actually walking up a wall all by himself, he's obviosuly using some sort of prop that the audience annot see. He also did a trick where he jumped into a puddle on the ground, fell through it and ended up at the top of a high building, and then kids were playing in the puddle to see if there was any holes. It was amazing.