Historical clue formulations

• Things that lead to Rome? — 2016-06-18
• Roman roads — 2015-09-22
• Roman roads — 2013-11-17
• Cerebral canals — 2013-02-23
• Anatomical aqueducts — 2011-09-09
• Anatomical passageways — 2011-07-07
• Anatomical passages — 2009-05-04
• Anatomical passages — 2009-02-22
• Anatomical passages — 2007-09-06
• Anatomical passages — 2004-09-05
• Brain passages — 2003-03-30
• Anatomical canals — 2002-02-09
• Sinuses, e.g. — 2000-09-16
• Anatomical canals — 1996-11-09
• Roman roads — 1996-05-23