Filled with Santiaguino weekend and vacation houses, 10 kilometers north of Maitencillo, Cachagua is an upscale village where kids ride docile horses and plump burros over hardpacked sandy roads. There are no accommodations, but the beachfront restaurant Los Coirones, reached via a staircase at the south end of Avenida Los Eucaliptos, is a good lunch alternative.

Opposite the west end of the beach, bring binoculars to view the Humboldt penguins and other seabirds at Conaf’s Monumento Natural Isla Cachagua, separated from the mainland by a 100-meter channel. Measuring only 300 by 150 meters, the nearly barren granitic island harbors a breeding population of 1,000 to 2,000 Humboldt penguins, roughly 10 percent of the global population and 15 percent of the Chilean population. There are also brown pelicans, cormorants, oystercatchers, Dominican gulls, and other bird species, while sea lions and otters frolic offshore, the otters subsisting on the abundant shellfish. While divers take some sea urchins and other shellfish, the human disturbance is minimal.