The early history of California is on display at its missions, most of which still exist and are museums. Between 1769 and 1823, the Spanish fathers who travelled north from Mexico founded 21 missions. I have visited several – San Diego, San Luis, Sonoma, Carmel, and Santa Clara. Some have changed little. Others burned down and were rebuilt, so what you see has more recent origin.
Many missions remain active churches. Some are located in other complexes, such as Santa Clara (on a university campus) or Sonoma (connected with the old California militia museum). Because they are churches, if you go on weekends, it is common for weddings to occur. This has limited my success in taking interior photographs.