Stumped by this Dec. 26, 1991 event? Find the crossword answer now!

– It ended on Dec. 26, 1991
– It was a country
– It was a union of multiple republics
– It was once the largest country in the world
– It had a communist government
– It was a superpower during the Cold War
– Its capital was Moscow
– It spanned across Europe and Asia
– Its official language was Russian
– It had a rivalry with the United States during the Cold War