Crissy Field in San Francisco

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War is for the birds at Crissy Field, a military airstrip turned waterfront nature preserve with knockout Golden Gate views. Where military aircraft once zoomed in for landings, bird-watchers now huddle in the silent rushes of a reclaimed tidal marsh. Joggers pound beachside trails and the only security alerts are raised by puppies suspiciously sniffing surfers. On foggy days, stop by the certified-green Warming Hut to browse regional-nature books and warm up with fair-trade coffee.