Native peoples of America had no immunity to the diseases that European explorers and colonists brought with them. Diseases such as smallpox, influenza, measles, and even chicken pox proved deadly to American Indians. Europeans were used to these diseases, but Indian people had no resistance to them.
Answer:
Due the probability of a German counterattack, the Westen Allies engaged into an initial defensive against any likely invasion by creating a system of fortresses on the frontier but also leaving gaps to be able to canalize any German attack; one of those offensives around 1914 in WWI was called <em>"The First Battle of the Marne"</em>, resulted in a victory for the Allies.
The Soviet and USA decided to end the space race.
