Across
1
Mountain that can erupt with lava
3
Half of the Earth
5
Cold treeless Arctic plain
6
Large body of water partly enclosed by land
8
Deep narrow valley with steep sides
9
Land surrounded by water
11
Chain or group of islands
Down
2
Largest ocean on Earth
4
Line dividing two countries
7
Largest river in South America
10
Land surrounded by water on three sides