There's no denying that Gigi Hadid is a force to be reckoned with. Not only has she already conquered the fashion world at age 21, but she is also insanely hot. And, not to mention, so is her boyfriend, Zayn Malik. With so many accomplishments under her belt, it's time we honored the supermodel by looking back at her sexiest bikini moments. You might want to turn on the AC for this one, because things are about to heat up!