On November 6, 1985, the M-19 stormed the Colombian Palace of Justice and held the Supreme Court magistrates hostage, intending to put president Betancur on trial. In the ensuing crossfire that followed the military's reaction, some 120 people lost their lives, as did most of the guerrillas, including several high-ranking operatives and 12 Supreme Court Judges. Both sides blamed each other for the outcome. This marked the end of Betancur's peace process.
The Armero tragedy was one of the major consequences of the eruption of the Nevado del Ruiz stratovolcano in Tolima, Colombia, on November 13, 1985. The lahars picked up speed in gullies and engulfed the town of Armero, killing more than 20,000 of its almost 29,000 inhabitants. Casualties in other towns, particularly Chinchiná, brought the overall death toll to 23,000.
On 15 November 1985, Thatcher and FitzGerald signed the Hillsborough Anglo-Irish Agreement, which marked the first time a British government had given the Republic of Ireland an advisory role in the governance of Northern Ireland.