People who know the geography of San Francisco City and County usually think of it as a seven mile by seven mile square at the northern tip of the San Francisco Peninsula.  The little known fact is that the City boundaries extend to include the Farallon Islands, a 211-acre archipelago of rocks and islands nearly due west of the Golden Gate Bridge.  Closed to the public and inhabited by only about a half dozen researchers, this area has legitimate claim to the title of "roughest neighborhood in the City."