That humongous glass cube across from the Plaza Hotel is actually the biggest Apple Store in the world (at 18,000 square feet). It opened in early 2006, and only closed when Hurricane Sandy shuttered the entire city (it’s open 24/7). Along with the genius bar is a 46-seat theater and more than a dozen Internet-connected computers loaded with games—geek paradise. Apple has opened several other branches, including one in Grand Central Station.