James Magnussen

Magnussen's rapid rise has earned him the nickname "The Missile," and it doesn't sound like he'll be satisfied until he reaches the rarest of heights. After clinching his spot at the London Games with the fourth-fastest time ever in the 100-metre freestyle (47.10 seconds), the 21-year-old Australian issued a warning to his rivals: "Brace yourselves," he said in March. "I'm going to be doing everything within my power to break that world record, because I do want to be considered the fastest man in history." In fact, Magnussen already has the fastest time for anyone not wearing one of the now-banned bodysuits formerly allowed in competition, but he'll still be taking aim at Cesar Cielo's mark of 46.91 seconds in London. He figures to be the favorite for gold after winning at last year's world championships while Cielo finished fourth. Magnussen also helped the Aussies take gold in the 4x100-metre freestyle relay and silver in the 4x100 medley relay at that event. In addition to those relays and the 100 free, the brash youngster could contend for a medal in the 50-metre freestyle in London after winning at the Australian trials in 21.74 seconds, also perhaps within striking distance of Cielo's world record (20.91). "I'll certainly be confident going into London," Magnussen said. "People are going to sit up and take notice."