Subject
- Physiographys24
- Population24
- Rapids24
- Reefs24
- Rivers24
- Runways (Aeronautics)24
- Waterfalls24
- Mines and mineral resources20
- Oil storage tanks20
- Salt mines and mining20
- Storage tanks20
- Industrial sites18
- Vegetation and climate16
- Vegetation boundaries16
- Vegetation mapping16
- Environment15
- Parks15
- Recreation areas15
- Chimneys14
- Cooling towers14