Subject Region
United States
12
Mars (Planet)
4
Asia
3
Outer space
3
English-speaking countries
2
Europe
2
Great Britain
2
Des Moines (Iowa)
1
Developing countries
1
Earth (Planet)
1
East Village (New York, N.Y.)
1
Espana
1
Great Plains
1
Iowa
1
Lassen Volcanic National Park (Calif.)
1
Mongolia
1
Moon
1
New Orleans (La.)
1
New York
1
New York (State)
1
Roswell (N.M.)
1
Spain
1
Sri Lanka
1