America's biggest bank has officially opened its new and long-awaited headquarters at 270 Park Avenue in Manhattan — complete with a new state-of-the-art gym, an Irish pub, a social "exchange" above the trading floors, and more. Employees had begun trickling into the $3 billion building in early autumn, and on October 21, JPMorgan held a ribbon-cutting ceremony . The tower was lighting up the New York City skyline long before the October grand opening. The Jamie Dimon -led bank behemoth first