Twyfelfontein, which means as much as „doubtful fountain“ or „Fountain of Doubt“ is the name of a valley in the Damara highland. This valley was inhabited by the Damara, who call the valley Uri-Ais (jumping fountain) in their language. Twyfelfontein is famous because of its many rock paintings and rock engravings (Petroglyphs) of the San (Bushmen) of which 2500 were counted. Specifications about the age of the engravings fluctuate and a period of 1000 – 10000 years is stated. The valley was declared a national monument in 1952 to stop the common stealing of rock engravings. The paintings/ engravings can only be visited with a local guide. UNESCO declared Twyfelfontein as World Heritage Site in 2007.