In the past, where did humans tend to settle and why?

In the past a lot of cultures used to move from place to place for several reasons as the climate, the topography and other advantages. They were looking for places with fertile land to develop farming and other jobs that were important for to live and take care of their families. In those times they didn't actually have the luxury to choose a job and if they had it was very difficult. An other reason of moving is because wild animals or other tribes have attacked to their area and threw them out. Some tribes, like Kozakhs from the norther China  waited until their animals ate all the grass of the land and then they moved. Others moved for a period and then they returned to their homelands or its land they chose to live, for example Mongols used to live like this. From the past years people used to change places and they chose the ones that they interest them, so do we when we change houses for economical or other reasons and even countries for our jobs