- United States | 216, 216, 20
- Country in North America | 0, 216, 23
- North America | 0, 216, 24
- Americas | 0, 2k, 35
- Continent | 0, 4k, 111
- Earth | 0, 4k, 128
- Solar System | 0, 4k, 130
- Orion Arm | 0, 4k, 131
- Milky way | 15, 4k, 132
- Local group | 0, 4k, 133
- Virgo Supercluster | 0, 4k, 134
- Astronomy | 0, 4k, 146
- Natural science | 0, 64k, 2k
- Science | 0, 69k, 2k
- Ciro Santilli's Homepage | 262, 237k, 4k
- Heavy water | 59, 59, 2