Fifteen years ago this week, on the night of 20 August 1968, Russian tanks rolled across the Czechoslovak border to begin an occupation that shocked the world. With the help of archive material, some never before seen in the West, the BBC's Diplomatic Editor John Simpson recalls those dramatic days. In the space of a few short hours troops from the Soviet bloc moved into Prague, took over key installations and hauled the local leaders off to Moscow. For the Russians, Mr Dubcek 's liberalising regime had gone too far. It was time to bring the Czechs to heel.
Chief picture editor DUNCAN HERBERT Produced by GORDON CARR A BBCtv News special