On July 17, 1981, the Hyatt Regency Hotel in Kansas City hosted a crowded tea dance inside its atrium. Hundreds of guests filled the lobby, while others gathered on suspended walkways overlooking the space below. The walkways were supported by steel rods connected to the ceiling. During construction, a small design change altered how those rods were attached, unintentionally doubling the load on a critical connection. The flaw went unnoticed. At 7:05 p.m., the fourth-floor walkway collapsed onto