Map of plans for improvements to Sixth Avenue. In the 1900s, the "hump" cut took place in the downtown area known as Grant's Hill. The project began with planning in 1909 and ended with the final cut in 1913. It changed the gradient of Grant Street, Diamond Street, and Oliver, Fifth, Sixth, Webster and Wylie Avenues. For more information, please see Frederick Law Olmstead, Pittsburgh Main Thoroughfares and the Down Town District: http://digital.library.pitt.edu/cgi-bin/t/text/text-idx?c=pitttext&view=toc&idno=00aep1324m
