Cenote Azul

This guide to Cenote Azul near Cancún opens at the rim, where the water darkens into one of the deepest sinkholes on this stretch of coast. It traces the geology linking this cenote to the nearby Bacalar Lagoon, the Lake of Seven Colors, separated today by only a thin wall of limestone that is slowly dissolving. You'll hear why swimming here means moving between two very different temperatures within minutes, and who tends to greet your feet first. Paddle the lagoon's shallows before slipping into the cenote's cooler water.