What was the purpose of the Nuremberg trials which took place 1945 to 1949?

Chief US Prosecutor said it best in his opening statement:

"The wrongs which we seek to condemn and punish have been so calculated, so malignant, and so devastating, that civilization cannot tolerate their being ignored, because it cannot survive their being repeated. That four great nations, flushed with victory and stung with injury stay the hand of vengeance and voluntarily submit their captive enemies to the judgment of the law is one of the most significant tributes that Power has ever paid to Reason."

"The common sense of mankind demands that law shall not stop with the punishment of petty crimes by little people. It must also reach men who possess themselves of great power and make deliberate and concerted use of it to set in motion evils which leave no home in the world untouched."