 Complete the following phrase:  On December 9, in anticipation of the protest, several of the prisons involved were placed on lockdown. While the strike was initially planned as a one-day event, it was extended for several more days after prisoners reported that prison officers at several of the prisons had responded to the strike with violence. On December 15, multiple news sources announced that the strike was over. That same day, an article published in ColorLines called it the largest prison strike in U.S. history. Following the strike action in Georgia, similar large-scale prison strikes were held at prisons in several other U.S. states, including Illinois, North Carolina, Virginia, and Washington. Several years later in 2016, a nationwide prison strike, referred to as one of the biggest prison protests in modern history, was held during the 45th anniversary of the 