Historical clue formulations

• Completely collapses — 2026-02-04
• Lunar landscape features — 2025-05-13
• Much of the moon's landscape — 2016-06-08
• Fails miserably — 2011-04-10
• Astronomical collision results — 2008-12-14
• Much of the surface of Mars — 2001-07-17
• Bomb aftermaths — 1997-03-16
• Holes in the ground — 1996-04-06