You step off the highway before dawn and the van hums toward Chiquilá, the small fishing town where the mainland surrenders to Gulf water. The boat chops away from the dock and the bay opens into a blue that seems to push outward, daring you to leave the city behind. By midmorning you’re threading between sandbanks, the boat’s wake sketching white lines across shallow turquoise. Holbox arrives slowly — a low strip of palms and painted houses, gulls negotiating the breeze, and hammocks draped over waist-deep water that tempts you to stop and float.