A wind tunnel study was conducted to investigate the flow characteristics near three configurations of high-rise buildings- an isolated high-rise building, two high-rise buildings separated in the streamwise direction, and two high-rise buildings separated in the streamwise direction, but situated atop a terrace-shaped lower level. A pulsed-wire anemometer was used with an automated traversing system to make detailed velocity measurements in the vertical centerplane and in a horizontal plane just above the surface. For each of the three basic configurations, measurements were taken while systematically varying the building height or, for the twin buildings, varying both the height and separation between the buildings. The measured mean velocity components were used to construct plots showing velocity vectors and streamline patterns and, hence, the height and downwind extent of areas of recirculating flow. The mean flow streamline plots were used to identify emission source locations that might result in adverse concentrations on the downwind building face.