The topography of Greater London is relatively gentle, characterized by a wide river valley and low-lying rolling hills. The elevation generally rises as one moves away from the River Thames towards the outer boroughs.
* **Highest Point:** Westerham Heights, located in the London Borough of Bromley on the southern edge of the city, reaching an elevation of 245 meters (804 feet) above sea level. * **Lowest Point:** The River Thames, which is tidal and sits at sea level. * **Hills and Elevations:** Notable high points within the urban footprint include Hampstead Heath (134 meters / 440 feet) in the north, offering panoramic views of the city, and Shooters Hill (132 meters / 433 feet) in the southeast. * **Flood Plains:** The areas immediately adjacent to the Thames in central and eastern London are natural flood plains. Due to the city's vulnerability to storm surges from the North Sea, the Thames Barrier was constructed in the early 1980s to protect the capital from flooding.