The fragmented societies were vulnerable to attack and unable to survive independently, as some controlled the fertile farmland and others controlled the goldmines.
The consolidation in the goldmining industry stepped up a notch as Newmont, which is based in Denver, agreed to buy Goldcorp, a Canadian rival, in a $10bn deal.
“I’ve watched it evolve from essentially the forgotten land above 96th street, where no one really saw any value, to the goldmine and the gold coast that it has become of Manhattan.”