China was one of the first civilizations in the world. This civilization, unlike the others, was actually very isolated from the rest of the ancient civilizations. The main reason for the isolation were the natural barriers. Between China and the other civilizations were standing the largest mountain range in the world, the Himalayas, and several large deserts. This discouraged people both from China and from the other civilizations from moving through this areas and see what's on the other side. This resulted in developing a very unique culture in China that was not influenced by any other culture. Also, this civilization was developing totally independently, and it actually managed to surpass the other civilizations in many aspects, while they were not even aware of its existence, or just knew that it existed but had no real idea about it. China only opened up properly to the world after it was invaded and ruled by the Mongols.
Large areas of Europe were conquered by Muslims. When these areas such as southern Spain were recaptured and placed under Christian rule Muslim customs and architecture remained. Christians were encouraged to go on Crusade to recapture Jerusalem from the Muslims.
Americans feared that the Soviet Union hoped to spread communism all over the world, overthrowing both democratic and capitalist institutions as it went.
