Historical clue formulations

• South American grasslands — 2023-11-28
• Grasslands of South America — 2023-06-15
• Landforms seen in South America — 2023-05-20
• South American plains — 2017-09-17
• Grasslands — 2015-12-19
• South American plains — 2012-12-24
• Grassy plains — 2011-04-14
• Grasslands — 2008-08-14
• Grassy plains — 2008-06-08
• Prairies — 2006-03-12
• South American plains — 1997-01-16