sentences:  About 60 existing houses were demolished, with white residents moved to the Roper Hill community and cottages for African-Americans built on a 40-acre tract northwest of the Cahaba Project called "Washington Heights" or, more commonly, "The Forties".Local landscape architect W. H. Kestler designed a relatively dense suburban layout with 400 houses on 1/2 to 3/4 acre lots encircling a central green space called "The Mall".The design was approved in 1936 and constructed over the following two years.