Mexican President Gustavo Díaz Ordaz orders soldiers to suppress a demonstration of unarmed students, ten days before the 1968 Summer Olympics will start.

On October 2, 1968 in the Tlatelolco section of Mexico City, the Mexican Armed Forces opened fire on a group of unarmed civilians in the Plaza de las Tres Culturas who were protesting the upcoming 1968 Summer Olympics. The Mexican government and media claimed that the Armed Forces had been provoked by protesters shooting at them, but government documents made public since 2000 suggest that snipers had been employed by the government.

The number of deaths resulting from the event is disputed. According to U.S. national security archives, American analyst Kate Doyle documented the deaths of 44 people; however, estimates of the actual death toll range from 300 to 400, with eyewitnesses reporting hundreds dead. Additionally, the head of the Federal Directorate of Security reported that 1,345 people were arrested.The massacre followed a series of large demonstrations called the Mexican Movement of 1968 and is considered part of the Mexican Dirty War, when the U.S.-backed Institutional Revolutionary Party (PRI) government violently repressed political and social opposition. The event occurred ten days before the opening ceremony of the Olympics, which were carried out normally.

Gustavo Díaz Ordaz Bolaños (Spanish pronunciation: [ɡusˈtaβo ˈði.as oɾˈðas]; 12 March 1911 – 15 July 1979) was a Mexican politician and member of the Institutional Revolutionary Party (PRI). He served as the President of Mexico from 1964 to 1970.

Díaz Ordaz was born in San Andrés Chalchicomula, and obtained a law degree from the University of Puebla in 1937 where he later became its vice-rector. He represented Puebla's 1st district in the Chamber of Deputies from 1943 to 1946. Subsequently he represented the same state in the Chamber of Senators from 1946 to 1952 becoming closely acquainted with then-senator Adolfo López Mateos.

Díaz Ordaz joined the campaign of Adolfo Ruiz Cortines for the 1952 election and subsequently worked for the Secretariat of the Interior under Ángel Carvajal Bernal. He became the secretary following López Mateos' victory in the 1958 election, and exercised de facto executive power during the absences of the president, particularly during the Cuban Missile Crisis. In 1963, the PRI announced him as the presidential candidate for the 1964 election, he received 88.81% of the popular vote.

His administration is mostly remembered for the student protests that took place in 1968, and their subsequent repression by the Army and State forces during the Tlatelolco massacre, in which hundreds of unarmed protesters were killed.After passing on presidency to his own Secretary of the Interior (Luis Echeverría), Díaz Ordaz retired from public life. He was briefly the Ambassador to Spain in 1977, a position he resigned after strong protests and criticism by the media. He died of colorectal cancer on 15 July 1979 at the age of 68.