| Clue | Source | Date |
|---|---|---|
| Safe room barrier | LA Times Daily | 17 Oct 2020 |
| Safe room barrier | The Washington Post | 17 Oct 2020 |
| Vault entrance | Wall Street Journal | 31 Oct 2015 |
| Vault entrance | ||
| Fort Knox feature | New York Times | 06 Oct 2008 |
| Fort Knox feature | ||
| Vault feature | ||
| Vault feature | ||
| Safe entry? |