Historical clue formulations

• What covers the North Pole — 2025-10-20
• Large white sheet — 2024-05-05
• Contracting sheet — 2022-03-05
• Geographical feature of Mars — 2019-02-21
• One of two polar opposites — 2018-07-06
• Top of the world — 2017-07-30
• Pole topper — 2017-05-05
• Feature of Earth, Mars and Pluto — 2017-04-15
• Martian feature — 2016-11-05
• Cold cover? — 2011-08-04
• Top-of-the-world topper — 2010-10-28
• Global warming panel concern — 2010-01-31
• Polar feature — 2010-01-24
• Martian feature — 2008-11-13
• One in the pole position? — 2004-10-07
• Greenland sight — 2002-11-16
• Most of the Arctic Ocean — 1999-11-24
• Polar buildup — 1999-04-14
• Martian feature — 1998-02-22
• Polar feature — 1997-04-01
• Cold pack? — 1997-03-23
• Polar cover — 1995-06-20
• Polar covering — 1995-01-02
• Hangover soother? — 1994-07-04