Up on Russian Hill there are several buildings that for various reasons escaped the sweeping destruction of the 1906 earthquake and fire. 1652-56 Taylor, near the Vallejo steps, survived under a barrage of seltzer water and wet sand. Another survivor, 1067 Green between Jones and Leavenworth, is one of the city's two remaining octagonal houses. Our favorite, though, is the handsome six-level house designed by architect Willis Polk for use as his home and office. Situated at the end of a quiet cul-de-sac right on the edge of the cliff where Vallejo Street plunges into North Beach, this homey hilltop castle employs Polk's signature brown-shingle style and simple white trim with flower-lined brick pathways and redwood decks commanding fantastic views of the Bay Bridge, the East Bay hills, and the sprawling city below. This lovely little block of trees, lawns, side streets, and balustrades also features two other pre-quake homes and two ornamented approach ramps that were designed by Polk.