In an unprecedented lockdown of a major U.S. city, Boston area residents were told to stay inside for much of Friday during a manhunt for the surviving suspect in the Boston Marathon bombings case.
A bustling metropolitan area came to an eerie stand-still as law enforcement officers combed neighborhoods. Boston's regional transit system was shut down. Colleges and schools closed. Amtrak train service was halted. Authorities ordered all taxi services to stop. The Federal Aviation Administration set up a no-fly zone over Watertown area.
Here are some images from an unforgettable day that gripped the nation.