What was the purpose of Olmec cities?

Trading helped Olmec build their urban centers of San Lorenzo and La Venta. These cities, however were used predominantly for ceremonial purposes and elite activity most people lived in small villages.

If I have to write about Daniel Hale Williams, first of all I would say that he was an excellent doctor. He was the fist one in openning an interracial staff hospital and also the first in practising  an open-heart surgery. I think he is an admirable person who even though he had a very poor childhood, he could overcome the difficulties, the poverty, tbe distance from his family and the racism and he fought for his dreams.