The first experimental heart transplantation was performed by Demikhov in Moscow in the very early 1940s. His experiments were discontinued during World War 2 but, when resumed in 1946, he produced a large volume of work devising 24 different methods of heterotopic heart transplantation within the chest. During the 1950s, many research workers transplanted the heart in the orthotopic position and also transplanted the heart and lungs en bloc. They used various methods, including cardiopulmonary bypass (heart-lung machine). During the 1960s, Lower and Shumway established beyond doubt that heart transplantation was a possibility. Christiaan Barnard, using their surgical techniques, performed the first human-to-human heart transplant, in December 1967 in Cape Town.