On Sunday 11, butterflies will flutter in the stomachs of 45,000 runners. But for some athletes, that excited, nervous, oh-my-gosh-this-race-is-about-to-begin–feeling will be about more than just banking a personal record. It'll be about the whopping $450,000 in prize money that's up for grabs (plus, potentially hundreds of thousands more in all-time-course-record bonuses). Click through the slide show above for pics and bios of the top male and female athletes gutting it out over 26.2 miles for places in history—and fatter wallets.