Archaeologists have discovered ancient documents in which Nebuchadnezzar boasted of the glory and splendor of Babylon. [1][source]
"The palace from which he surveyed Babylon was one of the citadels on the north side of the city. It had large courts, reception rooms, throne room, residences, and the famous hanging gardens, a vaulted, terraced structure with an elaborate water supply for its trees and plants, apparently built by Nebuchadnezzar for his Median queen. From the palace he would see in the distance the city"s27km outer double wall, which he had built. His palace stood just inside the double wall of the inner city, which was punctuated by eight gates and encircled an area3km by1km, with the Euphrates running through it. The palace adjoined a processional avenue that Nebuchadnezzar had paved with limestone and decorated with lion figures, emblematic of Ishtar; this avenue entered the city through the Ishtar Gate, which he had decorated with dragons and bulls (emblems of Marduk and Bel). It continued south through the city to the most important sacred precincts, to whose beautifying and development Nebuchadnezzar had contributed, the ziggurat crowned by a temple of Marduk where the god"s statue resided. In Marduk"s temple there were also shrines to other gods, and in the city elsewhere temples of other Babylonian gods, restored or beautified by Nebuchadnezzar." [2][source]
Josephus quoted the ancient writer Berossus who in his Chaldaic History gave a description of Nebuchadnezzar"s building activities. [2]1 [source]
"The discovery of the cuneiform inscriptions has remarkably confirmed the accuracy of this vs. From these we learn that Neb. was primarily, not a warrior, but a builder." [4][source]