Subject
- Marine accidents3
- Mines and mineral resources3
- Navigation3
- Reefs3
- Salt mines and mining3
- Vegetation boundaries3
- Aqueducts2
- Chimneys2
- Communication2
- Contours (Cartography)2
- Cooling towers2
- Demography2
- Electric power transmission2
- Geysers2
- Hot springs2
- Human settlements2
- Hydrographic surveying2
- Industrial sites2
- Lakes2
- Marshes2