Tuesday marks the 40th anniversary of the beginning of one of the greatest social upheavals of the 20th century.
By Rupert Wingfield-Hayes
BBC News, Beijing
On 16 May 1966, Chairman Mao launched the Great Proletarian Cultural Revolution.
Chinese leader Mao Zedong warned that "representatives of the bourgeoisie" had infiltrated the Communist Party and intended to establish a dictatorship.
It was a movement that tore China's society apart at the seams and still haunts China to this day.
Exactly 40 years ago on Tuesday, Chairman Mao made a dramatic call on China's youth to overthrow the country's Communist Party leadership.
His call was heeded by millions of radical youths, who came to be known around the world as the Red Guards.
China was plunged into turmoil. Hundreds of thousands died, millions more were brutalised and tortured, and much of China's cultural heritage was left in ruins.
By the end of 1968, the revolution had brought China to the brink of civil war.
To this day debate still rages over what motivated Chairman Mao.
At the time many saw it as a huge social experiment - an attempt to smash China's old society and build a new one on its ruins.
But many researchers now believe Mao used the cultural revolution to destroy his rivals inside the Communist Party, and to reassert his supreme power over China.
In that, he succeeded, but at massive cost.
In 1968, to end the violence, Mao ordered the Red Guard to be disbanded.
Millions of young Chinese were packed off to the countryside to learn from the peasants.
Their exile lasted for 10 years or more, and some are still there today.