San Francisco’s Presidio National Historic Landmark has been the centerpiece of the city by the bay since 1776. When Spain colonized California, the Presidio (or fort) was established here for the purpose of guarding San Francisco Bay. Comprising 1,500 acres, the Presidio is a vast and varied park with plenty to do for everyone. This park stretches along the Bay all the way to the southern end of the Golden Gate Bridge. You can walk or bike the Presidio, but even better, two different free shuttles will give you a complete overview of the grounds.