The Giants' Playground is a bizarre rocky landscape near Keetmanshoop, near the Quiver Tree Forest, in the south of Namibia. The piled up dolerite rocks look as if they were the work of giants, but they were created by block weathering, an angular variant of wool sack weathering. (Wikipedia)
A permit is required to visit, which you can get at the Quiver Tree Forest and is valid for both.