| Name | Hollow Earth Monument |
| Address | 454 S 3rd St, Hamilton, Ohio, 45011, United States |
| Date | 0000-00-00 |
| Time | 00:00:00 |
| Category | unknown |
| Description | A memorial for an outsider theorist who believed that the planet is actually hollow.... |
| Coordinates | 39.39480, -84.56240 |
| Web address | /places/hollow-earth-monument |