The spiral glass staircase uses a very thick and well-reinforced circular core, upon which the outer sidewalls are attached. From there, the treads and landings are attached,. The staircase rises 14 treads to a landing, then another 11 treads to the second floor. It duplicates this pattern to the third floor. An elevator is around an adjacent corner, just out of view. Interestingly, the location of the elevator is just forward of the second and third levels, so a glass bridge was constructed on those levels to connect the floor to the elevator lobby. Apple is calling this store the largest in New York City, although if you tally up the retail floor square-footage (7,200 s.f.), it seems like it has less display space than Fifth Avenue or SoHo. The footage is less because the second and third levels don't occupy the entire footprint of the building, just the rear 50 feet or so. - Apple Inc.