Soviet, Polish, Hungarian and Bulgarian troops enter Czechoslovakia on the night of 20/21 August 1968. Romania firmly refuses to participate. The invasion is condemned by the legitimate authorities of Czechoslovakia, who urge people not to engage in armed resistance (still, about 100 citizens of Czechoslovakia are killed). Dubcek is arrested along with his associates and taken to Moscow, where after a few days he is coerced to abandon all his reforms.
Daria Czarnecka: Warsaw Pact invasion of Czechoslovakia