Region
Adirondack Mountains Region
1
Adirondack Mountains Region (N.Y.)
1
Africa
13
Africa, East
1
Africa, North
1
Africa, Sub-Saharan
2
Africa, West
1
Alabama
1
Alagnak Wild River
1
Alagnak Wild River (Alaska)
1
Alaska
22
Alberta
2
Alberta, Northern
1
Allegheny Portage Railroad National Historic Site
1
Allegheny Portage Railroad National Historic Site (Pa.)
1
Amazon River Region
18
Amazon River Valley
2
America
17
American Samoa
1
Antarctica
1
Antietam National Battlefield
1
Antietam National Battlefield (Md.)
1
Antilles britanniques
1
Appalachian Mountains
1
Appalachian Region
1
Appalachian Region, Southern
3
Appomattox Court House National Historical Park
1
Appomattox Court House National Historical Park (Va.)
1
Aral Sea (Uzbekistan and Kazakhstan)
1
Arctic Ocean
1
Arctic Regions
2
Arctic regions
14
Arizona
2
Asia
6
Athabasca Tar Sands (Alta.)
1
Atlantic Coast
5
Atlantic Coast (Brazil)
2
Atlantic Coast (Ga.)
1
Atlantic Coast (S.C.)
2
Atlantic Coast (U.S.)
1
Australasia
4
Australia
23
Bahamas
1
Balkan Peninsula
1
Bering Land Bridge
2
Berlin
1
Big Bend National Park
1
Big Bend National Park (Tex.)
1
Blue Mud Bay (N.T.)
1
Boston Region
1
more ...