> "Note also there's a tendency to congregate in many coastal areas, likely related to the ability to harvest food from the ocean." Maybe, but if you have boat

> "Note also there's a tendency to congregate in many coastal areas, likely related to the ability to harvest food from the ocean." Maybe, but if you have boats to go fishing then the easiest way to get 100 miles away to make a new settlement will be by boat and that coincidentally leaves your new settlement on the coast as well. 100 miles slog through undeveloped land and around valleys and hills and carrying all your supplies on your back is much harder. Same with your comment about valleys, the easiest way through land is to float down a river and that will include going through a valley and your new settlement being on the river in a valley, and the last settlements being at the river mouth and on the coast. And water makes for the easiest trade routes - a camel train can only compete in temperate open plains, not in polar regions or the harshest deserts or thick jungle. > "humans don't appear to like living in deserts and polar regions [..] deep-seated genetic preference for living in valleys and grasslands with nice views?" Perhaps a deep-seated genetic preference for drinking water and not freezing to death?