Who was Nebuchadnezzar?

Well, there were two. The first being the king of the Babylonian Empire from 1125 to 1103 BC. His greatest contribution was securing Babylon from the Elamites. The second, Nebuchadnezzar II, was ruler of Babylon during the Chaldean Dynasty. He defeated Judah and Jerusalem and forced the Jews into exile. He is also credited with creating the Hanging Gardens of Babylon.