Captive in Babylon

Babylon, the main subject of not only the second half of the Old Testament but one of the main focal points of Revelation. A great and mighty nation that has given us visions of it magnificence with pictures of great structures, of hanging gardens along great and towering walls. A city and nation that dwelt in opulence with all that a nation could ever want. The trading place of all things East and West, a melting pot of harmony and diversity. Ruled over by kings who were cruel and decisive, greatly feared by all the nations around who had been absorbed into the great and might kingdom of Babylon. How did it become so and why did it become so, why is so great a portion of Scripture surrounding it?