Why was the Sperrgebiet area of southern Namibia closed to most visitors?

The Sperrgebiet, a region located within the Namib desert, was closed to unauthorized visitors primarily due to the discovery of major diamond deposits in 1908.1

Following these discoveries near the port of Lüderitz, the German colonial government prohibited public access to the area to protect mining interests. This restriction was maintained for decades as various mining entities, most notably Consolidated Diamond Mines of South West Africa, Ltd., held a monopoly on the region's lucrative diamond-bearing gravels.1

Access remained strictly controlled until the early 21st century, when the area began transitioning toward conservation and tourism. The region was eventually gazetted as the Sperrgebiet National Park in 2008 and opened to the public in 2009.1