This is an amazing urban parkour video.

If you have not seen parkour before you need to see this.
Some of these guys would make the hardest ninja proud. The way they can scale walls is inspirational, and is truely on the edge of your seat viewing.

One slip and it is all over, these guys take huge risks jumping from rooftop to rooftop, up and down again. You would have to ask yourself how mad the first person to make the leap is....

Best watched in high definition if your connection can handle it.

Parkour is defined in wikipedia as:

Parkour (sometimes abbreviated to PK), or l'art du déplacement (English: the art of movement) is the physical discipline of training to overcome any obstacle within one's path by adapting one's movements to the environment. It is a non-competitive, physical discipline of French origin in which participants run along a route, attempting to negotiate obstacles in the most efficient way possible. Skills such as jumping and climbing, or the more specific parkour moves are employed. The goal of a practitioner of parkour, called a traceur if male, or traceuse if female, is to get from one place to another using only the human body and the objects in the environment. The obstacles can be anything in one's environment, but parkour is often seen practiced in urban areas because of the many suitable public structures available such as buildings and rails.

The term freerunning is sometimes used interchangeably with parkour. While freerunning is more to do with expressing yourself within your environment, parkour is aiming to get from A to B the fastest. However, there is some controversy over the exact definitions of the two terms. Though disputed, many "parkour purists" say that the biggest difference has to do with theatrics. Free-running involves a lot of trick moves, particularly aerial rotations and spins. Because these moves are merely showy, not economical, and do not actually help the participant to get from place to place, they are considered contrary to the nature of parkour. A free-runner may also move backwards in order to make a move as flashy as possible. This is contrary to the philosophy originally laid down by David Belle. Although Sebastian Foucan co-founded parkour, he is more often associated with the sport of free running.