Subject
- Towers43
- Cities and towns40
- Cliffs39
- Fault zones39
- Landforms39
- Mines and mineral resources38
- Salt mines and mining38
- Vegetation boundaries38
- Marine accidents35
- Navigation35
- Reefs35
- Hydrography34
- Hydrographic surveying31
- Dams29
- Inland Waters29
- Communication28
- Human settlements26
- Aqueducts25
- Buildings25
- Contours (Cartography)24