demonstration in Londonderry (Derry), Northern Ireland, on Sunday, January 30, 1972, by Roman Catholic civil rights supporters that turned violent when British paratroopers opened fire, killing 13 and injuring 14 others (one of the injured later died). Bloody Sunday precipitated an upsurge in support for the nationalist Irish Republican Army, which advocated violence against the United Kingdom to force it to withdraw from Northern Ireland.

Bloody Sunday began as a peaceful—but illegal—demonstration by some 10,000 people organized by the Northern Ireland Civil Rights Association in opposition to the British government's policy of interning nationalists without trial. The demonstrators marched toward Guildhall Square in the city centre, but the British army had cordoned off much of the area, prompting most of the marchers to alter their course and head toward Free Derry Corner. However, some of the demonstrators confronted the soldiers, pelting them with stones and other projectiles. British troops responded by firing rubber bullets and a water cannon. Ordered to arrest as many demonstrators as possible, the army proceeded to confront the marchers, and violence erupted. Who fired the first shot remains a point of contention—the army maintained that it fired only after being fired upon, while the Roman Catholic community contended that military snipers opened fire on unarmed protesters—but the result was clear: after less than 30 minutes of shooting, 13 marchers lay dead.

British Prime Minister Edward Heath (Heath, Sir Edward) immediately ordered an inquiry, which was led by Lord Widgery, the lord chief justice of England. Widgery concluded that the demonstrators fired the first shot but that none of those dead appeared to have carried weapons. The Londonderry coroner, however, was unequivocal, calling the deaths “unadulterated murder,” and nationalists campaigned for more than two decades for the government to establish a new inquiry. Finally, in 1998 Prime Minister Tony Blair (Blair, Tony) ordered a new investigation, chaired by Lord Saville. Among other findings, the commission confirmed in 2004 that none of those killed in the shootings were armed.

(January 9 【January 22, New Style】, 1905), massacre in St. Petersburg, Russia, of peaceful demonstrators marking the beginning of the violent phase of the Russian Revolution of 1905. At the end of the 19th century, industrial workers in Russia had begun to organize; police agents, eager to prevent the Labour Movement from being dominated by revolutionary influences, formed legal labour unions and encouraged the workers to concentrate their energies on making economic gains and to disregard broader social and political problems.

In January 1905 a wave of strikes, partly planned by one of the legal organizations of workers—the Assembly of Russian Workingmen—broke out in St. Petersburg. The leader of the assembly, the priest Georgy Gapon, hoping to present the workers' request for reforms directly to Emperor Nicholas II, arranged a mass demonstration. Having told the authorities of his plan, he led the workers—who were peacefully carrying religious icons, pictures of Nicholas, and petitions citing their grievances and desired reforms—toward the square before the Winter Palace.

Nicholas was not in the city. The chief of the security police—Nicholas's uncle, Grand Duke Vladimir—tried to stop the march and then ordered his police to fire upon the demonstrators. More than 100 marchers were killed, and several hundred were wounded. The massacre was followed by a series of strikes in other cities, peasant uprisings in the country, and mutinies in the armed forces, which seriously threatened the tsarist regime and became known as the Revolution of 1905.