Historical clue formulations

• Come back again (again ... again ...) — 2021-09-05
• Bounce around a canyon, say — 2012-08-21
• Come back again — 2011-07-22
• Come back again — 2006-08-06
• Have a canyonlike effect — 2003-08-17
• Come back again — 1998-10-15
• Deep canyon feature — 1997-11-22
• Come back again — 1997-06-05