Early expeditions—such as Charles Bruce's in the 1920s and Hugh Ruttledge's two unsuccessful attempts in 1933 and 1936—tried to ascend the mountain from Tibet, via the North Face. Access was closed from the north to Western expeditions in 1950 after China took control of Tibet. In 1950, Bill Tilman and a small party which included Charles Houston, Oscar Houston, and Betsy Cowles undertook an exploratory expedition to Everest through Nepal along the route which has now become the standard approach to Everest from the south.