Fans pose for photos outside of the stadium in Mexico City on Tuesday. Juancho Torres/Anadolu/Getty Images See all topics Email Link Copied! The World Cup kicks off tomorrow, with defending champion Argentina looking to become just the third team ever to win back-to-back titles. Lionel Messi came off the bench to score in Argentina's final warmup match before 88,000 fans in Alabama. Meanwhile, tiny Curaçao is set to become the smallest nation by population to ever compete in the men's tournament.