The flag of the Soviet Union consisted of a plain red flag with a gold hammer crossed with a gold sickle placed beneath a gold-bordered red star. This symbol is in the upper left canton of the red flag.

The hammer and sickle (Unicode: U+262D ☭ HAMMER AND SICKLE) is a communist symbol representing proletarian solidarity between agricultural and industrial workers. It was first adopted during the Russian Revolution at the end of World War I, the hammer representing workers and the sickle representing the peasants.

Red star. The red five-pointed star is a symbol of the ultimate triumph of the ideas of communism on the five (inhabited, excluding Antarctica) continents of the globe. It first appeared as a military symbol in Tsarist Russia. It was then called the “Mars star,” reminiscent of Mars, the ancient Roman god of war.