On July 1, 1862, the retreating Army of the Potomac reached the James River after six days of fighting outside of Richmond. Confident in the support of nearby navy gunboats, Maj. Gen. George McClellan’s men occupied Malvern Hill on the north bank of the river. McClellan ordered the hilltop fortified with artillery batteries to cover the open fields that fronted the hill, and arranged his infantry with the V Corps on the west slope and the III and IV Corps on the eastern side with a strong reserve in the rear. Confederate commander Gen. Robert E. Lee believed a sustained artillery barrage could weaken the Union position before his infantry attacked. Around 1:00 p.m., both sides opened an artillery duel which was largely ineffective. Lee ordered in his infantry, but the attacks were not coordinated properly and advanced at different times, stalling short of the hill’s crest. The Federal artillery was the deciding factor, repulsing every attack and resulting in a tactical Union victory. The next day, McClellan withdrew to Harrison’s Landing on the James, ending the Peninsula Campaign and the Seven Days battles to capture the Confederate capital.
Operation Barbarossa was the Nazi German military invasion of the "USSR", since this was the famous surprise attack by Germany that broke the Nazi-Soviet Pact in World War II.
I believe the answer is: The importance of having little or no gap between classes
Socialism tend to view that society should not have economic class and prefer the government to took control of the country's resource and distribute it among the people. The soviet union who adopt this view and crumbled fail to see that economic class would automatically exist because people have different talents and put more efforts in their life.
believed that the function of the government was to encourage voluntary cooperation among groups with the same interest; that the government should guide the relief efforts not participate