Across
1
Low-lying land surrounded by higher ground
4
Vast body of salt water
5
Large natural elevation of earth
6
Where river meets the sea
9
Wearing away of land by water or wind
12
Imaginary line around the middle of Earth
Down
2
Region surrounding the North Pole
3
City that is seat of government
7
Large natural stream of water
8
Largest river in South America
10
Largest ocean on Earth
11
Deep narrow valley with steep sides