Region
United States --
16
Europe --
10
United States
5
Africa --
4
Soviet Union --
4
Great Britain --
3
Japan --
3
Developing countries --
2
Former Soviet republics
2
Former Soviet republics --
2
Great Britain
2
Korea (North) --
2
Korea (South) --
2
New York
2
New York (State) --
2
Soviet Union
2
20th Century
1
Afghanistan --
1
Africa
1
Asia
1
Developing countries
1
East and West
1
Europa --
1
Japan
1
Korea (North)
1
Large, David Clay
1
Mediterranean Region
1
Mediterranean Region --
1
Nepal
1
Pacific Area --
1
United states --
1