Parkour is an urban extreme sport and i happily am a participant of this art of movement (also known as freerunning) and i am trying to advertise my youtube channel http://www.youtube.com/user/parkourhyo plz subscibe =) and watch my vids Parkour: http://www.youtube.com/watch?v=hOVrj6xMWr8 My editors editing showreel (not parkour related): http://www.youtube.com/watch?v=9tKUNLGsoZk
Paris, London, many of the European and South American cities would have fantastic architecture for free-running.
In Australia we're not so lucky. There is very little in the way of accessible nooks and crannies and alleys, so the only people who actually get into them are:
a) reckless b) trespassing c) often drunk d) end up horribly injured.
However I still find the way of parkour very handy in my daily life. With parkour there is no such thing as "getting lost" and "have to go around", more like "finding a quicker route" and "go straight over"!
Free running is so awesome and if I wasn't so self conscious of everyone watching I would do it more often. Wall running up 12 feet feels awesome. Can't do any aerial tricks though.