The Spanish occupation of Upper California began in 1769 at the site of the first mission, San Diego de Acala.  In the next fifty years, twenty more missions were founded in a chain that stretched 650 miles up the coast of California to 

Sonoma spaced roughly a stiff day's ride apart.  For 68 years these remarkable institutions dominated the spiritual and economic life of this last outpost of Spain, until they were dismantled by the Mexican authorities and ultimately submerged in the tide of Americans that eventually took over the province.  Abandoned, left to disintegrate, the buildings crumbled one after another under the attack of weather and vandals.  In time, all were restored; some well, some inadequately, and today, as they have for decades, they still draw thousands of the devout and the curious to their musty churches and mellowed arcades.   The oldest historical relics in the state. . . indeed, on the Pacific Coast.