Region
Africa
4
Aids and devices
1
Alaska
1
Antarctica
1
Arctic regions
1
Asia
3
Australia
9
Babylonia
2
Books and reading
1
California
4
Canada
5
Central America
1
China
8
Ciudad Juárez
2
Denmark
1
Detroit
2
EE.UU
1
Earth (Planet)
1
Education (Elementary)
1
Education (Secondary)
1
Egypt
1
El Paso
2
England
6
English-speaking countries
1
Europe
4
Florida
1
France
2
Georgia
1
Germany
1
Gettysburg National Military Park (Pa.)
1
Ghana
1
Great Britain
122
Greece
3
Hawaii
1
Hiroshima-shi
3
Hunters Point (San Francisco, Calif.)
1
India
3
Iowa
2
Iraq
3
Israel
1
Japan
8
Jimmy Carter National Historic Site (Plains, Ga.)
1
Kenya
1
Kuwait
1
Manitoba
3
Mars (Planet)
1
Media
1
Mexico
6
Michigan
4
Missouri
2
more ...