Historical clue formulations

• Vertical strip on a map — 2015-06-17
• Alaska or Hawaii — 2011-12-30
• China has only one — 2011-06-09
• Mountain, e.g. — 2008-04-25
• Mountain, e.g. — 2007-10-06
• Atlantic or Pacific — 2002-04-07
• Pacific, e.g. — 2002-01-05