Volunteers quickly descended on Ground Zero to help in the rescue and recovery efforts. At Jacob Javits Convention Center, thousands showed up to offer help, where they registered with authorities. Construction projects around the city came to a halt, as workers walked off the jobs to help at Ground Zero. Ironworkers, welders, steel burners, and others with such skills were in high demand. By the end of the first week, over one thousand ironworkers from across North America had arrived to help, along with countless others.