What was the Berlin-Rome-Tokyo Axis? Why did Italy join the side of Germany and Japan in the Second World War?

Rome-Berlin-Tokyo Axis was the alliance between Italy, Germany, and Japan who fought against Allied forces in World War II. It created a defense alliance between the countries and was largely intended to deter the United States from entering the conflict.

Italy joined the Allies in the First World War to gain territories of Turkey and Germany. But she could get no part of the German and Turkish colonial empire. So, she felt cheated. Further, Italy was ruled by Mussolini and Germany was ruled by Hitler. The ideologies of both leaders were similar. They glorified wars and wanted to make their country powerful. Hence, Italy joined the side of Germany and Japan in the Second World War.