The Santa María School massacre was a massacre of striking workers, mostly saltpeter works (nitrate) miners, along with wives and children, committed by the Chilean Army in Iquique, Chile on December 21, 1907. The number of victims is undetermined but is reliably estimated at over 2,000. It occurred during the peak of the nitrate mining era, which coincided with the Parliamentary Period in Chilean political history (1891–1925). With the massacre and an ensuing reign of terror, not only was the strike broken, but the workers' movement was thrown into limbo for over a decade. For decades afterward there was official suppression of knowledge of the incident, but in 2007 the government conducted a highly publicized commemoration of its centenary, including an official national day of mourning