Lake Otjikoto is one of only two lakes in Namibia is actually a sinkhole that was formed by a collasing karst cave. It spans 102m in diameter but its depth is still unknown as it tapers into a laterla cave system. When the Herero moved into the area they named it Otjikoto, meaning 'deep hole'.
During World War I the German Schutztruppe sumped their war materials in the lake before surrendering to the South African and British troops in order to prevent them from using them. Many of the larger pieces were recovered and are on display in the Tsumeb Museum.