Here you can see the Ukrainian singer Irina Bilyk with a performance of the song Katyusha at a celebration of Victory Day in 2005, exactly 60 years after the end of the Great Patriotic War, as World War II called in Russia.
On May 7, 1945, at 02:41 in the morning, the German Chief of Staff Alfred Jodl (1890-1946) signed the unconditional surrender of Germany to the Allies in Reims (France). The document stated that all forces under German command would stop the hostilities on May 8, 1945 at 23:01 Central European Time.
The only representative of the Soviet Union at that time in Reims was General Ivan Alexeevich Susloparov (1897-1974) who acted as a liaison officer and who was not in direct contact with the Kremlin. Yet he signed the document for the Soviet Union, because no one would wish to create the impression that Germany would surrender without the cooperation of the Soviet Union.
Stalin, however, did not appreciate how things went. He stated that the Soviet Union, and not the Allies, had made the largest contribution to the victory over Germany. Moreover, he found that the agreement should have been signed in Berlin, the center of the Nazi aggression. The protocol of Reims, as he called it, had to be considered as a preliminary agreement.
And so, on May 8, 1945, shortly before midnight, a second ceremony was held in the Berlin headquarters of the commander of the Red Army, Marshal Georgy Konstantinovich Zhukov (1896-1974). The German Field Marshal Wilhelm Keitel (1882-1946) signed an identical document as the day before. Because of the time difference between Berlin and Moscow, the Russians consider that the Great Patriotic War did not end on May 8, but in the morning of May 9, 1945.
Therefore, since 1946, the Soviet Union started celebrating Victory Day on May 9. The Russians had to wait until 1965 to get a day-off for it though. The day was celebrated with great pomp and splendor, including the famous military parade on Red Square in Moscow.
In the '90s, after the collapse of the Soviet Union, the mass celebrations were reduced, but it changed again when Vladimir Putin came into power. Since then, Victory Day is again a day of massive celebrations with a great sense of national self-esteem, on which the popular culture plays a major role. The 60th anniversary in 2005 was the largest ever mass celebration in Russia, including this version of Katyusha by singer Irina Bilyk.