Karoo Karoo The Karoo ( ; from a Khoikhoi word, possibly "garo" "desert") is a semi desert natural region of South Africa. No exact definition of what constitutes the Karoo is available, so its extent is also not precisely defined. The Karoo is partly defined by its topography, geology and climate, and above all, its low rainfall, arid air, cloudless skies, and extremes of heat and cold. The Karoo also hosted a well-preserved ecosystem hundreds of million years ago which is now represented by many fossils. The Karoo formed an almost impenetrable barrier to the interior from Cape Town, and the
Karoo sills (see below), creating multiple flat-topped hills, or Karoo Koppies, which are iconic of the Great Karoo. The vegetation of the Upper is similar to the Lower Karoo, so few people make a distinction between the two. The main highway (the N1) and railway line from Cape Town to the north enter the Lower Karoo from the Hex River Valley just before Touws River and follow a course about 50 km south of the Great Escarpment up to Beaufort West. Thereafter, they gradually ascend the Great Escarpment along a broad valley to Three Sisters on the Central Plateau and the