Visitors can explore the grounds of this 18th-century, still-active mission, the state’s first. There are 21 missions dotting the California coast, and San Diego lays claim to the first. Established in 1769, Mission San Diego de Alcalá is the physical representation of Christianity’s birth on the West Coast. Even today, you can worship here—it’s an active parish with Mass held daily—but even if you aren’t a practicing Catholic, the mission is still a sight to behold, with white stucco walls, Spanish roof tiles, and grand archways. It stands on a hill overlooking Old Town with gorgeous views.