Walk to the top of Cerro de San Basilio and take a look around the old contaduria counting house and fort (built in 1770), where riches were tallied and stored en route to Mexico City or to the Philippines and China. Several of the original great cannons still stand guard at the viewpoint like aging sentinels waiting for long-dead adversaries.
Behind and a bit downhill from the weathered stone arches of the contaduria stand the gaping portals and towering, moss-stained belfry of the old church of Nuestra Señora del Rosario, built in 1769. Undamaged by war, it remained an active church until at least 1872, around the time when poet Henry W. Longfellow was inspired by the silencing and removal of its aging bells.
Downhill, historic houses and ruins dot San Blas  town. The old hotels Bucanero and Hacienda Flamingos on the main street, Juárez, leading past the central plaza, preserve much of their old-world charm. Just across the street from the Hacienda Flamingos, you can admire the restored, monumental brick colonnade of the 19th-century former Aduana, now a cultural center. Continue west along Juárez to the El Pozo estuary. At that shoreline spot, gaze across the El Pozo channel. This was both the jumping-off point for colonization of the Californias and the anchorage of the silk- and porcelain-laden Manila galleons and the bullion ships from the northern mines.
El Faro (lighthouse) across the estuary marks the top of Cerro Vigia, the southern hill-tip of Isla del Rey (actually a peninsula). Here, the first beacon shone during the latter third of the 18th century.
Although only a few local folks ever bother to cross over to the island, it is nevertheless an important pilgrimage site for Huichol people from the remote Nayarit and Jalisco mountains. Huichol have been gathering on the Isla del Rey for centuries to make offerings to Aramara, their goddess of the sea. A not-so-coincidental shrine to a Catholic virgin-saint stands on an offshore sea rock, visible from the beach-endpoint of the Huichol pilgrimage a few hundred yards beyond the lighthouse.
Sadly, a large cave sacred to the Huichol at the foot of Cerro Vigia was demolished by the government during the early 1970s to provide rock for a breakwater. Fortunately, President Salinas de Gortari partly compensated for the insult by deeding the sacred site to the Huichols during the early 1990s.
Two weeks before Easter, Huichol people begin arriving by the dozens, the men decked out in flamboyant feathered hats. On the ocean beach, 10 minutes’ walk straight across the island, anyone can respectfully watch them perform their rituals: elaborate marriages, feasts, and offerings of little boats laden with arrows and food, consecrated to the sea goddess to ensure good hunting and crops and many healthy children.