While at San Blas, we carpooled for a long day trip to visit the historic island town of Mexcaltitán, in a lagoon a 2½ hour drive from San Blas. There are no cars on the island, and access is from the road end by one of the many little ferry boats. Here is a view of the island as we approached on a ponga ferry.

Legend (and some archeological data) suggests that this is the site of the original Aztec city, Aztlán.