The Olympic spectacle is a lot like the Lee Valley Whitewater Centre in suburban London. For five days this summer the world's attention will be focused on this pump-driven facsimile of a Class IV creek, where the planet's best slalom boaters will compete for the sports biggest prize. Some will triumph, others will falter, and then the world will change the collective channel. The lights will go out, and the athletes will go back to the river to train. Rio is just four years away. — Jeff Moag