Nearly six months after breaking ground in the Historic Core, Onni Group is prepared to take its latest high-rise development into the sky. Last week, crews began laying rebar for the foundation a 49-story tower at 820 S. Olive Street, which is replacing a nearly one-acre surface parking lot. When completed, the project will feature 516 dwelling units above 4,500 square feet of ground-floor commercial space. The tower, which is being designed by the Canadian architect Chris Dikeakos, will rise to an architectural peak of 637 feet, becoming the tallest residential building in the City of Los Angeles. Renderings portray a modern, glass and steel structure featuring a podium-level amenity deck. 820 S. Olive Street is one of three Downtown developments from the Onni Group, which recently completed a 33-story tower a half-block south and is planning a two-building complex near Staples Center.