The basalt-and-granite Erongo massif is an extinct volcano that rises 1.200 m above a vast peneplain some 200 km north-west of Windhoek as the crow flies. Its central feature is the eroded core of a caldera or volcanic crater that caved in under the weight of lava. With a diameter of 35 km and a height of 2.329 m above sea level, Erongo is the largest but not the highest of the circular inselbergs.
