The Presidio is such a cute little area within the 7x7 square miles of San Francisco. It's almost a fortress or escape from the chaos of the city; somewhere to getaway where you feel like you're not even in a big city. There aren't buildings overpopulating the area, street lights everywhere, and people causing havoc in the streets in their day to day routine. It's much more like a little escape to Tahoe or Marin or somewhere more outdoorsy with crisp, non-city air!
The Presidio is San Francisco's biggest park - almost 50% bigger than Golden Gate Park! Historically, the Presidio was the northernmost military outpost until 1994, when it became a national park. AKA behave when you're there because you will face federal consequences for even misdemeanors, like speeding.