Urban art, by definition via Wikipedia, "is a style of art that relates to cities and city life often done by artists who live in or have a passion for city life". It spans a wide range of styles, but they usually carry some sort of message or purpose.

Julian Beever is a unique face in the art crowd in that he uses chalk as his primary weapon instead of stencils and spray paint like a majority of others. I suppose the fact that chalk washes off would also help keep him out of trouble (unlike the guys using stencils and spray paint..). Not so much into the political scene, Beever seemingly prefers light-hearted images for his audience to experience.

Noted. But how does he create these wild illusions?

Anamorphosis is form of art that when viewed from the correct angle, can provide a 3-D appearance (see photo). Using only a camera to aid him (it helps maintain perspective when he looks through the lens), Julian creates stunning pieces of art on the pavement using this method. Check out his official gallery for other great work (including drawings and canvas pieces.)