John C. Portman Jr., the Atlanta architect and developer has died at 93. The Georgia Tech–trained architect is credited with developing large downtown projects that revolved around the concept of the the atrium, which he turned into large and dramatic enclosed open spaces surrounded by multiple balconies, hundreds of rooms and capsule elevators rushing vertically from base to upper floors.  Portman—who often developed and partially owned his projects—thought of these megastructures as new downtowns and they were often built in old downtowns that had been decimated by urban renewal and middle class fight.