Across
1
Half of the Earth
4
Imaginary line around the middle of Earth
6
Region surrounding the North Pole
9
Wearing away of land by water or wind
10
Low area between mountains
11
Deep narrow valley with steep sides
12
Steep rock face at edge of land
13
City that is seat of government
Down
2
Cold treeless Arctic plain
3
One of seven major landmasses
5
Largest ocean on Earth
7
Ocean between Americas and Europe/Africa
8
Flat grassland in tropical regions