Babylon was probably established in Akkadian period (around 2300 BC) . The tower of Babylon – the ziggurat was built about 1780 BC in the time when Babylon become one of the most important cities in the world . According to some hypotheses Babylon temple tower ziggurat could be the mythical Babylon tower that Bible speaks about. The city grew up and in the period of 1595-1157 BC, it became the largest city in the world- at that time Babylon covered almost 3 km2. Babylon had two types of walls - inner city walls of Babylon were built of mud bricks and outer walls were surrounding a large area to the north, east and south. According to a legend Babylon should had been the place, where one of the Seven Wonders of the World was built – The Hanging Gardens of Semiramid. After the conquest of Babylon by the Persian Cyrus II. the Great, Babylon became the capital of the Persian Empire. In 331 BC the city Babylon was conquered by Alexander the Great, who after returning from a campaign to the east, died there. Babylon was destroyed and burned down in 130 BC. When constructing the city of Baghdad materials from the famous historic city of Babylon was used.