(August 23, 1572) was a series of murders carried out by Catholic mobs and the Swiss Guard against French Huguenots, an ethnic group of Protestants. It occurred a few days after the wedding of Margaret of Valois to the future King Henry IV. Catherine de' Medici, the mother of then-king Charles IX, allegedly ordered the murders two days after an assassination attempt on Huguenot leader Gaspard de Coligny. It is likely that the signal to begin the attacks was given by the ringing of matins bells at the church of Saint-Germain l'Auxerrois in Paris. The name of the massacre comes from the day on which it occurred, the night before the feast day of Bartholomew the Apostle.

(March 5, 1770) occurred when British troops stationed in Boston under Captain Thomas Preston opened fire on a crowd of civilians. Five men in the crowd were killed, including former slave Crispus Attucks. The crowd was originally upset that British private Hugh White had struck a wigmaker's apprentice in the head earlier that day. Massachusetts governor Thomas Hutchinson ordered an inquiry into the event, which led to the arrest of thirteen people. Eight soldiers were defended at their trial by John Adams, and six were acquitted of murder charges. A notable engraving of the Boston Massacre was made by Boston silversmith Paul Revere. British sources often refer to the massacre as "The Incident on King Street."

August 16, 1819) was a massacre in St. Peter's Field in Manchester, England during a protest led by Henry Hunt against the Corn Laws. Fourteen people were killed when British cavalry charged the crowd of tens of thousands. In the aftermath of the massacre, the government of Prime Minister Robert Jenkinson, the 2nd Earl of Liverpool, passed the Six Acts to curtail radical gatherings. The name given to the massacre alluded to Napoleon's final defeat at the Battle of Waterloo four years earlier. The events in Manchester inspired the founding of the newspaper The Manchester Guardian, the predecessor to The Guardian, which is still widely read today. Plotters angry over the Peterloo Massacre and the Six Acts formed the Cato Street Conspiracy in 1820 in the hope of murdering Liverpool and his entire cabinet.

December 29, 1890) was the killing of 200 to 300 Lakota Sioux on the Lakota Pine Ridge Indian Reservation near Wounded Knee Creek in South Dakota. The massacre began when, during an observation of the Ghost Dance ritual, a deaf Lakota named Black Coyote refused to surrender his rifle to James Forsyth's 7th U.S. Cavalry. After the rifle discharged, the cavalrymen opened fire. Miniconjou chief Spotted Elk was among those killed in the massacre, for which twenty soldiers were controversially awarded the Medal of Honor; despite frequent protests, those awards have not been rescinded by Congress. The day after the Wounded Knee Massacre, surviving Lakota confronted the soldiers in the Drexel Mission Fight. The historian Dee Brown titled his 1970 history of Native Americans in the West Bury My Heart at Wounded Knee.

January 22, 1905) is usually considered the first event of the Revolution of 1905 in Russia. The sequence of events leading up to the massacre began with the Putilov Incident, in which four ironworkers in St. Petersburg were fired because they were members of a labor movement. The resulting strike left St. Petersburg iwthout electricity. On January 22, Father Georgy Gapon of the Russian Orthodox Church led protestors on a march to the Winter Palace to petition Tsar Nicholas II for better working conditions and higher wages. The Imperial Guard fired on the protestors near the Narva Gate. The Revolution of 1905 ultimately led to the establishment of the Russian Duma (parliament) and the adoption of a new constitution. The term "Bloody Sunday" is also used for several other incidents, including several events in Ireland and Northern Ireland.

(February 14, 1929) was the murder of seven members of Bugs Moran's North Side Gang in Chicago. The murders were carried out by gangsters under the command of Al Capone. It is widely believed that former members of a gang known as Egan's Rats, including Fred Burke, were the gunmen. The victims were lured to a warehouse in Lincoln Park with the promise of crates of stolen whiskey, which was especially valuable during Prohibition. The only survivor was a dog named Highball. Jack McGurn, one of the gunmen, avoided charges in the massacre thanks to the so-called "Blond Alibi" after taking the chief witness against him across state lines and marrying her. The St. Valentine's Day Massacre turned public opinion against Capone and led to him being named "Public Enemy No. 1."

(beginning December 13, 1937 and lasting six weeks) was a period of mass murder committed in Nanking (today generally spelled "Nanjing") by the Japanese army early in the Second SinoJapanese War. At the time, Nanjing was the capital of the Republic of China. The Japanese troops were commanded by Prince Yasuhiko Asaka and Iwane Matsui. One famous anecdote from the massacre concerns a contest between two Japanese soldiers to kill 100 Chinese civilians with a sword. Since Japan was not yet at war with the various Western nations, Chinese civilians who were able to make their way into the "Nanking Safety Zone" around the foreign embassies were safe from harm. Episcopalian missionary John Magee extensively photographed the massacre. In 1997, the American-born Chinese author Iris Chang wrote a bestselling account of the massacre titled The Rape of Nanking.

(March 16, 1968) was a mass murder of at least 300 unarmed Vietnamese civilians in a hamlet codenamed "Pinkville" in Vietnam's Quang Nai Province by U.S. troops during the Vietnam War. The only man convicted for his role in the massacre was William Calley, who defended himself by saying he was "just following orders" given by Ernest Medina. Helicopter pilot Hugh Thompson Jr. attempted to radio for help and later rescued a four-year-old girl, for which he was awarded the Distinguished Flying Cross. Photographs of the massacre were taken by Ronald Haeberle. Seymour Hersh won a Pulitzer Prize for uncovering the events of the My Lai Massacre through extensive interviews with Calley. Hersh later broke the story of the mistreatment of detainees at Abu Ghraib Prison during the Iraq War.

(May 4, 1970) took place during a nonviolent anti-war demonstration by students at Ohio's Kent State University. The students were protesting the Nixon administration's bombing of Cambodia during the Vietnam War. Ohio governor Jim Rhodes called in the National Guard, which fired into the crowd and killed four students: Jeffrey Miller, Allison Krause, William Schroeder, and Sandra Lee Scheur. A photograph taken by John Filo of Mary Ann Vecchio kneeling over the body of Jeffrey Miller won the Pulitzer Prize. Ten days later, two students at the historically black Jackson State University in Mississippi were killed under similar circumstances, but those shootings received far less press attention. The protest song "Ohio" by Crosby, Stills, Nash & Young was written shortly after the massacre.

(June 4, 1989) were a series of student-led pro-democracy protests in Beijing's Tiananmen Square during the spring of 1989. One day after the death of former Politburo member Hu Yaobang, students gathered in the public square to demonstrate for greater political freedom. The students camped out in the square for over a month, and similar movements took place throughout China. One famous symbol of the protests was the Goddess of Democracy statue erected in the square. Within the Chinese government, Zhao Ziyang was sympathetic to the students' demands, but the paramount leader Deng Xiaoping viewed the protests as a challenge to his authority. Martial law was declared on May 20, and the People's Liberation Army began clearing the square late at night on June 3. The resulting massacre is sometimes known as the June 4 Incident. In an effort to circumvent Chinese censorship, some people also refer to the massacre using terms such as "May 35th" or "VIIV" (the Roman numerals for 6 and 4). A famous photograph, known as "Tank Man," shows an anonymous protestor standing in front of a row of tanks.