Why was the Battle of the Marne “the most strategically important battle of the entire war?”

Lipid deposits in the blood vessels can lead to a condition where there is hardening of the vessels.  What is this condition called? (E.21)

What effect did the industrial revolution, especially in textiles, have on American slavery?

According to Marx and Engels in The Communist Manifesto, all of human history up to the present has been the history of: 

The Battle of Verdun was a massive, ten-month long offensive launched by the Germans as part of a war of attrition. What is the purpose of a war of attrition, as exemplified by the German assertion that they would “bleed France white” at Verdun?

What did the French mean when they talked of their “civilizing mission,” their reason–or excuse–for pursuing imperialism in east Asia and Africa?

Who replaced Stalin as head of the USSR following Stalin’s death from a stroke in 1953 (good riddance)?

Karl Marx claimed his socialist worldview was “scientific” because it was based not on ideas, but on material forces, especially:

How was the Battle of Britain fought?

What event prompted the abdication of the Kaiser and the collapse of the German Empire?