Mesopotamia is made up of different regions. Northern Mesopotamia is made up of hills and plains. The land is quite fertile due to seasonal rains, and the rivers and streams that come from the mountains. Early settlers farmed the land and used timber, metals, and stone. Southern Mesopotamia is made up of marshy areas and wide, flat, plains. Cities developed along the Euphrates and Tigris rivers which flow through the region. Early settlers had to irrigate the land along the banks of the rivers in order for their crops to grow.