1968, a year of uprisings and dashed hopes

The United States facing defeat in Vietnam. Moscow defied in Czechoslovakia. Student uprisings in Berlin, Paris and Mexico. Fifty years ago the world was rocked by revolt and dashed hopes.

Here is a look back at the dramatic year of 1968.

Vietnam: US backs down

Washington had been pouring troops into Vietnam since the early 1960s to back the South Vietnamese against Viet Cong guerrillas supported by the communist North.

But a major guerrilla offensive in early 1968 forces it to reassess.

Starting from the Vietnamese New Year holiday Tet in late January, thousands of communist forces attack southern towns, including the cities of Hue and Saigon.

The surprise coordinated assault is ultimately beaten back but it turns public opinion against US involvement in the conflict.

By late March, US President Lyndon B. Johnson announces a partial halt in US bombardments of the North.

It is the start of a long process of US disengagement from Vietnam, which culminates with the fall of the Southern capital Saigon in 1975 and the reunification of Vietnam in 1976 under the North.

Talks open in Paris in May, as the French capital is rocked by student protests.

Youths rebel

Anti-war demonstrations that had started in the mid-1960s on university campuses in the United States and Europe with chants of "US, go home!" take on a new dimension in 1968.

Demonstration against the Vietnam war, October 21, 1967, Washington

Youths pour into the streets around the world to vent anger at the war and the capitalist status quo, but also to demand sexual freedom, feminism and -- even then -- protection of the environment.

In Germany, the attempted assassination in April of radical leftist student leader Rudi Dutschke unleashes a riot in Berlin. The unrest spreads to dozens of German cities.

In France, students demonstrate in Paris on May 10, battling police through the night. Two days later, workers join in and a strike paralyses the country for weeks.

President Charles de Gaulle dissolves the National Assembly on May 30 but his party comes back even stronger than before in June legislative elections.

The social movement is echoed in Italy, Turkey and Japan.

Spring crushed

The winds of revolt reach communist Czechoslovakia, where Alexander Dubcek becomes head of the ruling party in January and tries to introduce reforms for "Socialism with a human face".

Prague residents gathered at Wenceslas Square on August 21, 1968 to protest the deployment of tanks from the Soviet Union and its allies

But the Prague Spring is unacceptable to Moscow, which still dominates communist Eastern Europe. In August, it sends in tanks and soldiers, including from its communist allies, that crush hopes for change.

Poland has its own "spring" in March, a student revolt that is swiftly repressed by the harsh communist regime. As several of the student leaders are Jewish, the authorities launch an anti-Semitic campaign which sees thousands quit the country.

Mexico Olympics, a stage

In Mexico, police crack down on protesting students just ahead of the October Olympic Games. Many are killed: officials put the toll at 33, while foreign witnesses give a figure of between 200 and 300.

There is more defiance at the Games: medal winners Tommie Smith and John Carlos raise their fists on the podium in a Black Power salute that puts the spotlight on discrimination against African-Americans.

Assassinations

It is a dark year for the fight against the racial segregation plaguing the United States. Martin Luther King, a black pastor and Nobel Peace Prize winner, is assassinated on April 4 by a white escaped convict.

US black civil rights leader Martin Luther King at the landmark March on Washington, August 28, 1963. He was assassinated on April 4, 1968

His murder unleashes demonstrations across the country. Soon afterwards the president, Johnson, signs one of the last laws on civil rights demanded by the celebrated activist, an act that ends discrimination in housing.

On June 5, another political assassination rocks the United States: presidential hopeful Bobby Kennedy is shot by a Palestinian immigrant. The younger brother of president John F. Kennedy -- himself assassinated in 1963 -- dies the following day.

Biafra disaster revealed

In 1968, the world awakens to the humanitarian disaster in Biafra, which is battling Nigeria to maintain the independence it declared the previous year.

Images of starving Biafrans emerge and mobilise a new kind of international humanitarian effort, leading soon afterwards to the formation of Medecins Sans Frontieres (Doctors Without Borders).

The 30-month conflict and a Nigerian blockade eventually claim a million lives, many from starvation.