"TO get to the top of the world, Petra Franklin Lahaie ushers her two young daughters and their girly bikes through a set of heavy bronze doors, greets the 24-hour elevator operator in the Prussian blue uniform, rides up 35 stories past mostly vacant office suites, debarks next to an observation deck and Chinese-themed banquet room, passes through a portal marked "private residence," climbs two stories into a neo-gothic pyramid and enters a penthouse apartment.