Region
Africa, Southern
3
Alps
2
South Africa
2
Arizona
1
Columbia River
1
Costa Rica
1
Everglades
1
Everglades (Fla.)
1
Florida
1
Grand Canyon National Park
1
Grand Canyon National Park (Ariz.)
1
Hungary
1
Northwest, Pacific
1
Okefenokee Swamp (Ga. and Fla.)
1
Philippines
1
Pinatubo, Mount (Philippines)
1
Soviet Union
1
Transvaal
1
Witwatersrand Basin
1