What caused the collapse of the soviet union?

OK easy *cough* question; what caused the collapse of the soviet union? The catch is that you have to do it in under 20 words. All i want is a concise answer, help me understand! :-)
What caused the collapse of the soviet union?
The basic under twnety word answer is the same thing that sustained it, communism.





Try reading "Animal Farm," it's viewed as a predictive parralel to the Soviet Union. Predictive in that it came out before the fall of the Soviet Union. Parralel in that it seems to mimic the rise and eventual fall of the Soviet Union.
What caused the collapse of the soviet union?
Yearning for freedom in mankind is too strong to resist, no matter how long it takes to end an evil!





There: exactly 20 words!
Reply:Ronald Reagan thought he did!


The collapse of their economy ( that concise enough for you)
Reply:they ran out of money
Reply:Gorbachev's Perestroika=reform which also included public opinion that led to the fall of the USSR.