I suggest reading a book called "1491" , by Charles C. Mann .
When he first published his book, he was viewed as a Pariah.
And when scientific data and new research based on the questions he brought up , he was hailed as a hero.
Carbon testing, on the bottoms of the Great Lakes, Lake Titicacu, old Lake Texcoco, Lake Peten, Lake Nicaragua, Lake Paracho and Lake Chapala . Proved by carbons on the lake bottoms, that the Americas ( North, Central, South) had a population of over 140 million people, before Colonialization began in the late 1400's .