A series of amazing rooftop stunts in a BBC short film are all genuine, it has been revealed. Frenchman David Belle leaps across London rooftops, at one point jumping between two buildings 60 feet up. The 28-year-old does not use any safety wires, though some crash mats were placed out of view of the cameras.

Two French teenagers, David Belle and Sébastien Foucan, developed parkour in Lisses, a Paris suburb. They drew on their experience in gymnastics and martial arts, as well as the obstacle-course training that Belle's father underwent as a soldier in Vietnam. The name is derived from the French phrase, parcours du combattant, roughly translated as "military obstacle course." Practitioners of parkour are known as "traceurs." The boys look as if they're trying to outrun the police. They jump over a wall, drop 10 feet and somersault to break the impact of landing. They leapfrog over a garbage can and clear a bench. They dash a step up another wall, grip the top and shimmy over. But no one is chasing them. They're simply practicing parkour, the modern art of navigating through your environment with maximum efficiency. In the past few months, Bay Area youths have taken it up, and, if the demonstration last weekend was any indication, they've progressed by leaps and bounds. Most parkour fans are teenage boys, and it's easy to see why. All you need is a pair of sneakers - and a daredevil spirit. And because most boys have plenty of experience climbing trees and jumping off walls, in a sense they've been practicing parkour all their lives.