At the same time, America was in the grip of a social revolution. The civil rights movement had already achieved much by 1968 but many black activists were still frustrated by ingrained racism in U.S. society. When civil rights leader Martin Luther King was assassinated on April 4, 1968, race riots, looting and widespread arson erupted in more than 100 U.S. cities. The National Guard had to be mobilised and at least 19 people died.

In August, The Democratic National Convention in Chicago was the focus of further serious rioting. Feelings were already running high in the wake of Democratic contender Robert F. Kennedy's assassination in June. Some 12,000 police officers and thousands of demonstrators fought pitched battles for three days.

Violent protest wasn't confined to the United States. In London, 200 people were arrested after rioting outside the U.S. embassy in Grosvenor Square on March 17. Thousands of anti-Vietnam War protests clashed with police. There were similar scenes in October, after another anti-war demonstration.

In Paris, the rioting was so intense and lasted so long that some of those caught up in it believed the country was close to revolution. Trouble started on May 3, when students clashed with police following the closure of the Sorbonne. Students and university authorities had been at loggerheads for weeks.

Within days, rioting had spilled onto the streets and students had been joined by thousands of disaffected workers. Across France, an estimated 10 million workers went on strike. Students tore up cobbles and erected street barricades. They fought running battles with the notoriously heavy-handed CRS riot police. On May 29, the government ordered tanks to the outskirts of Paris in an effort to quell the rioting.

French President Charles de Gaulle eventually called an election for June 23. Ironically, he won easily.