The geography of London is divided into two main zones: highlands and lowlands. These zones have unique climates and other features.
The London highlands are made up of rugged hills, rocky mountains, valleys, and plains. This area has a cooler climate and is generally unsuitable for farming. A ridge borders the northern edge of the city that forms a series of hills like the Highgate Hill and Crouch Hill. The southern portion of the city includes a separate ridge with gentler hills. London's lowland zone, where much of its population is concentrated, includes gentle slopes and warmer temperatures.
A major factor in London's geography is the River Thames. It flows west to east across the London basin and is the largest river in the area. Several tributaries flow out of the Thames including Stamford Brooks, Counter's Creek, and Tyburn Brook on the left bank and Hogsmill River, Neckinger, and Beverley Brook on the right bank. London is also home to many canals constructed in the 18th century and used to transport goods.