What it is: A full-fledged, constantly changing, outdoors and arts destination with a weekend's worth of things to do.
What it was: A military base until the Army decamped in 1994.
Why does the Presidio keep evolving?: By 2013, the park must be financially self-sufficient.
What's with all the bulldozers?: It's a five-year project to replace the Golden Gate Bridge approach with a greener, safer parkway.
Park acreage: Nearly 1,500
What $7,800 gets you: A month's rent in a new ultra-green three-story town-house near the park's southern edge.
What $100 gets you: A night at Rob Hill, the city's only campground--they're group sites, so invite 29 of your friends.
More shiny new things: The hilltop Lobos Valley Overlook with views of the Pacific. And a 22-room guesthouse--the park's first overnight lodging that's under construction.
The latest in landscape art: British artist Andy Goldsworthy returns with Wood Line, a sinuous shape that he's making with downed eucalyptus branches. Take the free PresidiGo Shuttle to stop 47 and walk up Lovers' Lane; www.presidio.gov/experiences
A tranquil overlook: An easy walk from the Presidio Golf Course parking lot , the peaceful National Cemetery Overlook opens onto a sea of white crosses and, beyond, the bay. From shuttle stop 31, access the overlook trail from Nauman Rd.; presidio.gov
Cafe with a million-dollar view: Stop for lunch at Beach Hut Cafe, a light-on-the-land eatery that reuses rainwater and incorporates solar and wind power and salvaged redwood. The view from the recycled-plastic chairs out front rivals that at the Warming Hut cafe. $; East Beach; 415/561-7761
Disney north: Why, exactly, is the Walt Disney Family Museum here? His daughter lives in Napa--and the Bay Area is an animation hub. More scholarly gallery than theme park, the museum suits its 19th-century brick building. $20; waltdisney.org
A home for native plants: On Wednesday and Saturday afternoons, you can volunteer at Presidio Nursery, which is growing nearly 75,000 plants for the park and has a spiffy new net-zero-energy Seed and Plant Lab. parksconservancy.org (click on "Volunteer).
3 adventures: Crissy Field's sporty side
Catch some air: The pros at the new House of Air trampoline park say you can bounce away at least 700 calories an hour, and we believe it. $14/hour; reserve ahead; houseofairsf.com
Break away: Rent a decked-out bike at Sports Basement and the Presidio is yours to explore. On Sunday mornings, staffers lead free rides over the Golden Gate Bridge into Marin. From $20/day; sportsbasement.com
Climb the walls: Beginners learn the basics of belaying and experts sharpen their bouldering skills behind vast windows of the onetime motor-pool repair shop, now Planet Granite. Day pass $18; planetgranite.com