| Clue | Source | Date |
|---|---|---|
| Lascaux cave paintings, e.g | LA Times Daily | 13 Apr 2019 |
| Lascaux cave paintings, e.g | The Washington Post | 13 Apr 2019 |
| Lascaux cave paintings, e.g. | ||
| Cave painting, e.g | The Washington Post | 22 Aug 2018 |
| Cave painting, e.g | LA Times Daily | 22 Aug 2018 |
| Cave painting, e.g. |