While it was true that western lands were somewhat more fertile than the now-depleted lands of the East, many of the pioneers were attracted to the frontier in order to speculate in land, i.e. to purchase large quantities of cheap government land and to sell it at a profit to later comers
East Germany built the Berlin Wall to put a permanent stop for the
people to go or get access to the West. This happened during the Cold War when
West Berlin was considered a getaway place for people who want to escape the
rule of communism and flee into democracy that it supported.
I think its five. I am not certain though.
