The abundant coolant for fusion reactors, the ability of some ships to land in water and the option of a ship ditching into the water instead of making a crash landing in the city are all factors that have made seaside and riverside space port cities popular on human worlds. They are also convenient for planetary shipping to and from ships at the ports via river. The heat of the engines, the hulls constantly cooling from re-entry and the numerous high-powered power plants, all located near water, make such cities generally foggy and steamy places, but they are also vast centers of trade wielding impressive economic power.