It was on 2nd May 1945, that the Soviet Red Army captured Berlin and hoisted the Red Flag over the Reichstag (Parliament Building), thus ending the dream of Hitler to conquer the entire world. The war machinery of Nazi Germany was annihilated. It also was the starting point of the end of the II World War, in which more than 4 crores soldiers and civilians died.
The heroism of the Soviet Red Army and the sacrifice they have to make in order to defend USSR and the city of Stalingrad is one of the most pitched battle that the world has ever seen. The so called unassailable war machine of Hitler was stopped at Stalingrad by inch by inch, street by street fight in which lakhs of army on both sides were killed. After the victory of Stalingrad, Red Army advance pushed the Nazi army backwards, pushed them out of USSR and then marched to the city of Berlin, the capital of Nazi Germany. And Nazi war machine completely collapsed and the Red Army hoisted the Red Flag on 2nd May 1945.
The end of II World War entirely changed the world power equation. The imperialist powers like Britain France etc. had to vacate many of their colonies like India. The United Nations was formed with the intention to avoid another World War. The rest is history.