1944 London, Great Britain (cancelled)

The anticipated 1944 Summer Olympics, which were to be officially known as the Games of the XIII Olympiad, were cancelled due to World War II. They were to have been held in London,England, United Kingdom, which won the bid in a June 1939 IOC election over Rome, Detroit, Lausanne, Athens, Budapest, Helsinki and Montreal on the first ballot.
Because of the cancellation, London went on to host the 1948 Summer Olympics, awarded without election.

In spite of the war, the IOC organized many events to celebrate the fiftieth anniversary of its foundation at its headquarters in Lausanne, Switzerland. Held from 17 June to 19 June 1944, this celebration was referred to as “The Jubilee Celebrations of IOC” by Carl Diem, the originator of the modern tradition of the Olympic torch relay.

Polish Prisoners of War (POWs) in the Woldenberg (Dobiegniew) Oflag II-C POW camp were granted permission by their German captors to stage an unofficial POW Olympics during July 23 to August 13, 1944 and an Olympic Flag made with a bed sheet and pieces of coloured scarves was raised. The event has been considered to be a demonstration of the Olympic spirit transcending war.