Over time, various civilizations rose and fell. These profoundly influenced the shape of the world thereafter. Taking a closer look at major empires helps us better understand the process of change. Some of them started small and then grew bigger, others arose after a long fall, but all of them had the dream of expanding and leaving a legacy behind. The Persian Empire used the Babylonian and Assyrian model as an example to build its own civilization. The empire grew enormously, conquering many lands between Egypt and India to encompass a wide spectrum of religions, cultures and languages. It was ruled by an absolute monarchy. The monarch exercised full authority over the entire empire and ruled through an intricate administrative system of officials and local authorities. He also had a spy system to constantly alert him to important events as they occurred. The empire supported local religious cults to gain favor in the invaded lands. They have also been amazing at embracing everything new from these countries and making it their own. The monarch had a very advanced postal system that could transport messages on horseback across this vast empire with great efficiency. The wealth and power of this kingdom were demonstrated in its elaborate palaces, monuments, audience halls, and carvings. By comparison, Greek civilization consisted of small competing city-states with a population only a fraction of that of Persian. High mountains and steep valleys divide the Greek empire into small, independent city-states; in contrast to the Persian Empire which was a single, united entity. Since there wasn't much diversity in these city-states, they all shared the same religion and language. These independent nations are made up of a collection of towns and cities. Although small in size, it featured a surprising range of ethnic culture and linguistic diversity. Unlike the Chinese empire, which reflected a single common culture and belief, the Indian empire failed to have a centralized government due to its diversity. The only known large-scale polity in India is the Maurya Empire which encompassed all but the southern tip of the subcontinent. As we can see, the world's civilizations have gone through many modifications and changes over the years, also being influenced by the geography of the area in which it arose and the ethnic configuration of the population that lived there. We can now see more clearly how the current civilization became what it is, and we have learned many lessons from the brief downfalls of past civilizations that can help us move forward in a better way.