World War II: Winston Churchill and Franklin D. Roosevelt sign the Atlantic Charter of war stating postwar aims.

World War II or the Second World War was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were tried for war crimes.

Sir Winston Leonard Spencer Churchill was a British statesman, military officer, and writer who was Prime Minister of the United Kingdom from 1940 to 1945 and again from 1951 to 1955. For some 62 of the years between 1900 and 1964, he was a member of parliament (MP) and represented a total of five constituencies over that time. Ideologically an adherent to economic liberalism and imperialism, he was for most of his career a member of the Conservative Party, which he led from 1940 to 1955. He was a member of the Liberal Party from 1904 to 1924.

Franklin Delano Roosevelt, also known as FDR, was the 32nd president of the United States from 1933 until his death in 1945. He is the longest-serving U.S. president, and the only one to have served more than two terms. His first two terms were centered on combating the Great Depression, while his third and fourth saw him shift his focus to America's involvement in World War II.

The Atlantic Charter was a statement issued on 14 August 1941 that set out American and British goals for the world after the end of World War II, months before the US officially entered the war. The joint statement, later dubbed the Atlantic Charter, outlined the aims of the United States and the United Kingdom for the postwar world as follows: no territorial aggrandizement, no territorial changes made against the wishes of the people (self-determination), restoration of self-government to those deprived of it, reduction of trade restrictions, global co-operation to secure better economic and social conditions for all, freedom from fear and want, freedom of the seas, abandonment of the use of force, and disarmament of aggressor nations. The charter's adherents signed the Declaration by United Nations on 1 January 1942, which was the basis for the modern United Nations.