he looked forward as they drove into greenwood , and james waved to some men building a house and they waved back and he tooted his horn and marta explained how coming up here was the section of greenwood avenue known as the black wall street , lookie here ... ... and luther saw a black bank and an ice cream parlor filled with black teenagers and a barbershop and a billiard parlor and a big old grocery store and a bigger department store and a law office and a doctor 's office and a newspaper , and all of it occupied by colored folk .