Even though this ravishing Russian stunner didn’t appear on the cover of SI until 2011, she’s been heating up the inside pages since 2007. Clearly she has some pretty good genes, but the supermodel admits she has to work hard for that bodacious bikini bod; Shayk has been training with Justin Gelband for more than four years, doing a mix of boxing, Pilates, and band exercises. “You have to be tough. I'm not a lazy person and I push myself. I go to the gym three or four times a week when I'm not traveling,” she told Vogue.