Historical clue formulations

• Connecting strips — 2015-05-01
• Panama and Suez — 2010-12-23
• Panama and others — 2007-12-05
• Thin strips — 2004-04-01
• Panama and others — 2002-03-04
• Panama and others — 2002-01-01
• Strips on a map — 2001-02-23
• Connecting strips of land — 2000-04-04
• They're bicoastal — 1994-01-28