A poster in the year 1943 showing the flags of many of the members of the Allies, including the "Big Three"

The Allies, including Britain, France, the Soviet Union, and later the United States, joined World War II to stop Nazi Germany’s aggression and prevent the spread of totalitarianism. Britain and France declared war after Germany invaded Poland in 1939, while the Soviet Union and U.S. joined later after being directly attacked. The Allies fought to defend democracy, sovereignty, and restore peace in Europe and beyond.

Above are leaders of the "Big Three". They met to shape post-war Europe, revealing early tensions between democracy and communism. 

The Yalta Conference was held in February 1945, near the end of World War II, where the leaders of the Allied Powers—Roosevelt (U.S.), Churchill (U.K.), and Stalin (USSR)—met to plan for post-war Europe. They agreed on the division of Germany, the creation of the United Nations, and the promise of free elections in Eastern Europe. Though united against Nazi Germany, tensions between democracy and communism emerged, foreshadowing the Cold War.

Above is a propoganda poster from Japan, originating from the Showa era depicting Adolf Hitler, Fuminaro Konoe, and Benito Mussolini, the political leaders of the three main axis powers in 1940. 

The Axis Powers consisted of Germany, Italy, and Japan, who formed an alliance in the 1930s with the goal of expanding their territories and establishing authoritarian regimes. Led by Adolf Hitler, Benito Mussolini, and Emperor Hirohito, the Axis sought to overthrow the existing world order, challenging democratic nations and spreading fascism and militarism. Their aggressive invasions in Europe, Africa, and Asia ignited World War II, aiming to dominate and reshape the global balance of power.

Above is a photograph of the signing of the Triparite Pact. To the left, seated from left to right, are Saburō Kurusu (representing Japan), Galeazzo Ciano (Italy) and Adolf Hitler (Germany).

The Tripartite Pact, signed on September 27, 1940, formalized the military alliance between Germany, Italy, and Japan, solidifying the Axis Powers. The pact aimed to establish a mutual defense against the Allied Powers, with each country pledging to assist the others if attacked. It reflected the Axis’s shared goals of territorial expansion, militarism, and the overthrow of the existing world order. The alliance further strengthened the Axis Powers' resolve to challenge democratic nations and drive their aggressive expansion, contributing to the escalation of World War II.