The hook
An actual wild canyon in the middle of San Francisco — chert cliffs, a free-flowing creek, and resident coyotes — that a shocking number of locals have never heard of.
01Why it's worth it
Islais Creek runs open through the bottom of Glen Canyon, one of the last places in the city where a natural creek still flows above ground, between rocky outcrops that boulderers have used for generations. The canyon floor feels apart — willows, blackberry tangle, red-tailed hawks, and coyotes you'll likely hear if you come early ("I used to run from my house through the canyon and up Twin Peaks... especially when you hear the coyotes early in the morning"). The top-voted answer when AskSF was asked for real hidden gems was, verbatim, "Glen Fucking Canyon" — and the recurring theme underneath it was disbelief that people who've lived in SF for years don't know it exists. It also chains: from the canyon's top end you can climb through Glen Park's stairways onto Twin Peaks for a full city-wilderness traverse.
02How to experience it
Enter at Bosworth & O'Shaughnessy by the rec center (easy from Glen Park BART). Walk the canyon-floor trail north, take the upper trails back along the cliff line, and keep dogs and kids close at dawn/dusk — the coyotes are established residents. Combine with coffee in Glen Park village.