Hitler's Invasion of the USSR

German troops cross into the Soviet Union.
(Public Domain)
Although Hitler had signed a non-aggression pact with Soviet leader, Josef Stalin, he had always envisioned himself conquering the large country.  In June of 1941, Hitler assembled the largest invasion force in history and proceeded to invade the Soviet Union.  Over 4 million troops were used, along with 600,000 vehicles and an equal number of horses.  It was known as "Operation Barbarossa."

But Hitler would suffer a similar fate to Napoleon Bonaparte, who had attempted an invasion 129 years earlier.

As with all invasions of Russia, the Russian people turned to a scorched-earth policy. Rather than letting their homes and property fall into the hands of the enemy, they destroyed it themselves. Cities went up in flames.  Then, the Russian winter came.  Hitler's blitz stalled outside of Moscow.  His troops froze to death.

Although Hitler conquered large amounts of Soviet territory, he was unable to conquer the Soviet Union itself.  The next year, Hitler lost a major battle at the city of Stalingrad, which would eventually force him to retreat back to Germany. Most historians see this as Hitler's greatest mistake.

In the end, over 75% of Hitler's forces participated in this invasion.