Across
1
Largest river in South America
4
Line dividing two countries
6
Seasonal heavy rainfall
7
Flat elevated area of land
9
Tool for finding directions
Down
2
Land surrounded by water
3
Wearing away of land by water or wind
5
Cold treeless Arctic plain
8
Area where water covers the soil
10
Raised area of land, smaller than a mountain
11
Region between the two tropic lines