A great option for a weekend stay or a quick day trip, Isla Mujeres sits just off the coast of Cancún and offers beautiful beaches perfect for relaxation. Plus, it's one of the best places to go snorkeling in the world thanks to a unique underwater museum and one of the world's largest coral reefs, home to all sorts of colorful fish. See marine life from another perspective on a glass-bottom boat tour. When you want to catch some rays, Playa Norte is the most popular beach, framed by white sand, turquoise water and swaying palm trees.