Indy 500 winner killed in 15-car pileup

Dan Wheldon is transported to a medical helicopter following a crash during the IndyCar Series' Las Vegas Indy 300 auto race Sunday, Oct. 16, 2011, in Las Vegas. ((AP Photo/Isaac Brekken))

October 17, 2011 2:29:35 PM PDT
Race car drivers always know the worst can happen whenever they get behind the wheel. On Sunday, it happened to one of IndyCar's biggest and most popular stars.