Subject Region
Earth (Planet)
30
Solar system
22
America
19
Europe
18
Africa
9
North America
9
Rome
8
Southern States
8
United States
8
Mexico
6
Spain
6
Universe
6
Earth
5
India
5
Middle East
5
Africa, North
4
Asia, Central
4
England
4
Greece
4
Moon
4
Antioch (Turkey)
3
Arabian Peninsula
3
Australia
3
Bering Land Bridge
3
Egypt
3
Great Britain
3
Islamic Empire
3
Oxford
3
Uganda
3
Washington (State)
3
Cradle of Humankind World Heritage Site (South Africa)
2
Europe, Central
2
Europe, Eastern
2
Florida
2
France
2
Himalaya Mountains
2
Japan
2
Jequetepeque River Valley
2
Jequetepeque River Valley (Peru)
2
Kuiper Belt
2
Mediterranean Region
2
Mesa Verde National Park (Colo.)
2
New Zealand
2
Oaxaca (Mexico : State)
2
Orce
2
Palestine
2
Peru
2
Pluto (Dwarf planet)
2
Poland
2
Polynesia
2
more ...