EARTHDAY
| Date | Clue |
|---|---|
| 2023-02-16 | Event first observed in 1970 |
| 2020-05-10 | Observance first celebrated in 1970 |
| 2020-04-12 | April 22 |
| 2020-01-14 | April event that's "green" |
| 2019-08-07 | *Scarcity |
| 2004-12-20 | Environmentalists' celebration |
| 1998-01-21 | April celebration |