What evidence supports the claim that the soviet union was geographically huge?

The Soviet Union was geographically huge stretching across Phil's classroom wall map and it consisted of Russian Federation which occupied the largest part, 15 Soviet Republics, for example, Uzbekistan, Kazakh SSR, Georgian SSR, Armenian SSR, Estonian SSR and seven satellite countries in Eastern Europe i. e. Germany, Hungary, Poland, Czechoslovakia, Romania, Bulgaria and Albania which are now independent countries.