Bacalar
Bacalar Lagoon, the Lake of Seven Colors. Photo via Wikimedia Commons.
A small lakeside town on the Laguna de los Siete Colores, a freshwater lagoon whose waters shift through seven shades of blue. The 18th-century Fuerte de San Felipe guards the town, built against pirate raids when Bacalar was a key port. It is a slow, swim-and-sail stop on the road to Chetumal.