Babel is a city located on the plains of Shinar on the planet E'retz, the home world of humanity. It is the capital of the human race and one of the first cities built after the Flood. It is humanity's greatest city, focused around its greatest wonder, the Tower of Babel.
In OTL, Babel is supposed to be a reference to the city of Babylon, in modern-day southern Iraq. However, OTL Babylon was essentially dead sometime in the second century BC. Nonetheless, it continued to be somewhat occupied and a province of various empires until about 650 AD, by which time the city itself was essentially abandoned. The city suffered from constant warfare and a series of droughts as the Euphrates River shifted over time. To avoid these issues and give it a more central location, the city of Babel is located at the same location as OTL Baghdad, which was the Arab recreation of Babylon. This moves the city about 100 km north of OTL Babylon.