Transportation costs have played a crucial role in the creation of cities throughout history, and changing transportation costs in modern times have had much to do with the ways in which cities have continued to change around us. For most of the history of the human race, the transportation of people and  goods on land took place using human or animal power, and took place on water using currents, wind, or oars. Most cities were built before there were motorized vehicles on land or water, or of course in the air. The most fundamental fact is that land transport has always been far more costly than water transport, and especially so during the thousands of years before the invention of cars, trucks and trains. Even today, it is often cheaper to ship goods thousands of miles by water than to ship them hundreds of miles by land.

Thomas Sowell,  Economic Facts and Fallacies