Across
1
Line dividing two countries
4
Imaginary line around the middle of Earth
6
Low-lying land surrounded by higher ground
8
Flat grassland in tropical regions
9
Land surrounded by water
10
One of seven major landmasses
11
Region surrounding the North Pole
13
Height above sea level
Down
2
Deep narrow valley with steep sides
3
Large natural stream of water
5
Distance north or south of equator
7
Mountain that can erupt with lava
12
Piece of land jutting into the sea