Historical clue formulations

• San Francisco's ___ Tower — 2017-03-10
• San Francisco's ___ Tower — 2013-06-25
• San Francisco's ___ Tower — 2013-01-18
• ___ Tower (San Francisco landmark) — 1998-05-20
• San Francisco's___Tower — 1996-04-04
• San Francisco's _____ Tower — 1995-03-17