Historical clue formulations

• Panama, e.g.: Abbr. — 2017-03-12
• Neck: Abbr. — 2015-08-08
• Common canal locale: Abbr. — 2012-03-30
• Narrow strip of land: Abbr. — 2010-05-20
• Transcontinental bridge, e.g.: Abbr. — 2007-11-04
• Panama, e.g.: Abbr. — 2005-01-12
• Neck of land: Abbr. — 2004-07-25
• Canal locale: Abbr. — 2004-03-31
• Narrow strait of land: Abbr. — 2002-12-26