At the beginning, the humans in the desert gathered around a huge fertile sea.
Supplied with what seemed to be unlimted water ressources, they used that water to foster their lifestyle, their culture, their food culture. The four harbours grew and flourished over the time. At the peak of their wealth, they created four lighthouses, that would lead ships, as well, as people on the land to the cities. Nonetheless, the humans weren’t satisfied with what they could achieve and they started to enslave others to achieve even more wealth and power. But the natural water reservoir couldn’t spend water to such an expotentially growing culture.
Over thousands of years, the natural reservoir lowered and the distance of the water to the big cities grew. At first, humans invented complex subterranean water systems. But as the distance grew, even these systems were limted. Humans were forced to build new cities, at the new coasts. This continued over time until only a small pond was left, the once flourishing cities in ruins, dusty signs of megalomania.
With the large cities, left as a mystified story of eden, your people set out, to reach „paradise“ and escape the everlasting struggle to survive in the desert.