On this day in 1967, the Australian Prime Minister Harold Holt was officially presumed dead. Between 1949 and 1956 Holt was Minister for Immigration and Treasurer between 1958 and 1966. On December 17th 1967, Holt went swimming at Cheviot Beach in Victoria and was never heard from again. It is assumed that he drowned, and two days later he was officially presumed dead. Deputy Prime Minister John McEwen was then sworn in as Prime Minister. As his body was never found, there are many conspiracy theories about Holt’s disappearance, such as that he was kidnapped, abducted by aliens or committed suicide.