Parkour may have first taken off in France in the 1990s, but Krynin says the true home of this extreme sport, which requires participants to leap, climb and somersault across buildings, is Russia. "It ...

Daredevils "OlegCricket" and Ilya Bagaev scale the side of a 40-story building in Russia. Somersaulting and leaping around the edges, this video may make you a bit queasy. Produced by Emma Fierberg.