Region
- United States 154 Treffer
- China 4 Treffer
- Colorado 4 Treffer
- Kentucky 4 Treffer
- Outer space 4 Treffer
- Pueblo 4 Treffer
- Richmond 4 Treffer
- Russia (Federation) 4 Treffer
- Africa 2 Treffer
- Colorado River Watershed (Colo.-Mexico) 2 Treffer
- Developing countries 2 Treffer
- Everglades 2 Treffer
- Everglades (Fla.) 2 Treffer
- Florida 2 Treffer
- Klamath River Watershed (Or. and Calif.) 2 Treffer
- Louisiana 2 Treffer
- Mars (Planet) 2 Treffer
- Mexico, Gulf of 2 Treffer
- Nigeria 2 Treffer
- North America 2 Treffer
- Polar regions 2 Treffer
- Russia 2 Treffer
- Solar system 2 Treffer
- Virginia 2 Treffer