“Cortes was directly responsible for much of the carnage in Tenochtitlan, but the war was only a small part of a larger catastrophe for which blame is harder to assign. When Cortes landed, according to the Berkeley researchers Cook and Borah, 25.2 million people lived in central Mexico, an area of about 200,000 square miles. After Cortes, the population of the entire region collapsed. By 1620-25, it was 730,000, “approximately 3 percent of its size at the time that he first landed.” Cook and Borah calculated that the area did not recover its fifteenth-century population until the late 1960s.”