1975 - Lon Nol is overthrown as the Khmer Rouge led by Pol Pot occupies Phnom Penh. Sihanouk briefly becomes head of state, the country is re-named Kampuchea.
All urban dwellers are forcibly evacuated to the countryside to become agricultural workers. Money becomes worthless, basic freedoms are curtailed and religion is banned. The Khmer Rouge coin the phrase "Year Zero". (sound familiar?)
Hundreds of thousands of the educated middle-classes are tortured and executed in special centers. Others starve, or die from disease or exhaustion. The total death toll during the next three years is estimated to be at least 1.7 million.

1976 - The country is re-named Democratic Kampuchea. Sihanouk resigns, Khieu Samphan becomes head of state, Pol Pot is prime minister.

1977 - Fighting breaks out openly with Vietnam.
1978 - Vietnamese forces invade in a lightning assault.
1979 January - The Vietnamese take Phnom Penh. Pol Pot and Khmer Rouge forces flee to the border region with Thailand. The People's Republic of Kampuchea is established. Many elements of life before the Khmer Rouge take-over are re-established.