Alcatraz was our first port of call on the tourist itinerary. Here's a tip - book ahead. We would have been waiting two weeks for the first available ferry across if we hadn't. The island itself has a fascinating history too deep to delve into here, and the ferry ride itself is worth the trip over there, if not just to give a sense of how isolated the island is out in the bay. On this note a remark our tour guide made has stuck with me, regarding how devastating it was for the prisoners to be close enough to see and hear the joyous frolicking of the populous on a fine summers day, yet be hopelessly out of reach.
Just to mention other highlights of our stay included clam chowder in a sour dough bowl and sea-lion spotting on Pier 46 and a ride on the famous trolley system. The free trolley museum is well worth the stop to watch the massive wheels and cables at work moving the trolleys around.