- United States | 216, 216, 15
- Country in North America | 0, 216, 18
- North America | 0, 216, 19
- Americas | 0, 1k, 30
- Continent | 0, 3k, 81
- Earth | 0, 3k, 87
- Solar System | 0, 3k, 89
- Orion Arm | 0, 3k, 90
- Milky way | 15, 3k, 91
- Local group | 0, 3k, 92
- Virgo Supercluster | 0, 3k, 93
- Astronomy | 0, 3k, 105
- Natural science | 0, 49k, 1k
- Science | 0, 53k, 1k
- Ciro Santilli's Homepage | 262, 182k, 3k
- Heavy water | 59, 59, 2