In Mexico the number of competing nations exceeded 100 for the first time.
There were political issues in the shape of student demonstrations before the Games and a Black Power protest during the medal ceremony for the men's 200m.
Reports vary on the numbers of people killed as the Mexican authorities acted to quell the student disturbances — certainly no fewer than 40, possibly as many as 300.
Avery Brundage, who as president of the United States Olympic Committee in 1936 had refused to allow politics to prevent his nation from attending the Berlin Games, accordingly decided in his role as IOC president that the Mexico Games should proceed.
He also stood firm against the Black Power protests, delivered against a backdrop of calls within the United States for their black athletes to boycott the Games as a stand against racism within American society. Gold medallist Tommie Smith and third-placed John Carlos were expelled from the United States team.
Away from the politics the concern was about the altitude, and the thin Mexico air that made the endurance events even more draining and delivered some spectacular, even freakish results in the impact events.
Top of the list was Bob Beamon's leap into the long jump history books. The American posted 8.90 metres with his first attempt in the final and no one came close, not even Beamon with his second jump. He had beaten the world record by 55cms and the new mark would stand until 1991.
There were further world records in all the sprint events, in the women's long jump and the men's triple jump, a competition in which the pre-Games world record was beaten nine times and equalled twice.
The men's high jump was remarkable not so much for gold medallist Dick Fosbury's Olympic record but for a technique, which became known as the Fosbury Flop, in which the American approached the bar backwards and leapt over head first. The men's discus cemented a place in Olympic history for Al Oerter, who won his fourth consecutive gold medal in the event for the United States.
The domination of gymnasts and swimmers in the individual medals table was more apparent than ever. Věra Čáslavská added four gold medals and two silvers to the five from previous Games and Akinori Nakayama claimed four golds, a silver and a bronze.
Don Schollander added to his four gold medals from Tokyo with three more golds and a silver for the United States swimming team, a feat matched by Charlie Hickcox and exceeded by another American Jan Henne, the leading woman swimmer of the Games.
Mexico saw the Olympic debut of an 18-year-old who remained under the radar to a degree, collecting two golds as part of the freestyle relay teams and only a bronze and a silver from his individual events. But for Mark Spitz the best was yet to come.
The Games saw the end of an era in football, and in hockey. Hungary won the football title with victory over Bulgaria in a final which saw four players sent off, the silver medallists finishing with only eight men. It was Hungary's third football gold medal — a record they share with Great Britain — but they have never achieved better than silver since.
India's domination of hockey had been shaken in 1960 by defeat in the final against Pakistan and restored four years later with victory over their neighbours. But in 1968 they failed to reach the final for the first time.
Top three performances
1-Bob Beamon (USA) - His long jump performance of 8.90m added 55cm to the world record and stands as one of the most remarkable Olympic feats ever. His record stood until 1991.
2-Lee Evans (USA) - Knocked over three tenths of a second off the 400m world record, and his time of 43.29 was only bettered 20 years later by Bucth Reynolds.
3-Triple jumpers - Five world records were set by three athletes over two days of competition, with gold eventually going to the Soviet Union's Viktor Sanyeyev, ahead of Nelson Prudencio and Giuseppe Gentile.
Did you know?
East and West Germany competed as separate countries for the first time.
Although Dick Fosbury is credited with revolutionising high jump with his 'Fosbury Flop' technique, he never held the world record. His gold medal-winning leap of 2.24m was 4cm shy of Valeriy Brumel's world record, which stood until 1971.
Swedish pentathlete Hans-Gunnar Liljenwall was the first Olympian to be disqualified for doping - his drug of choice? Beer.