The german invasion of the soviet union

ended quickly with a german victory
was part of hitler's plan to gain "living space"
violated the terms of the nazi-soviet pact
resulted in the capture of moscow

 violated the terms of the Nazi-Soviet Pact.

Detail:

When Hitler broke his non-aggression pact with Stalin and invaded Soviet territory in 1941, he did so in a massive way, intending to secure a quick victory.  He sent over 3 million soldiers, and 3,000 tanks were involved in the attack.  The German generals had predicted that they could win in 10 weeks' time.  As we know, that didn't happen, and the war on the Eastern front between Germany and the USSR became the bloodiest theater of war in World War II.

The German invasion was termed "Operation Barbarossa" (meaning "Red Beard" after the nickname of an old German emperor, Frederick I (1122-1190), who had won victories for the German territories in the Middle Ages.