"Portugal too was ruled by ageing right-wing dictators.
They were fighting bloody wars to hold onto their colonies in Africa. But in the early morning of 25 April 1974 tanks moved out of barracks in Lisbon.
Most shops weren't open yet; a young woman was buying flowers before starting her job at a café. A young soldier approached her and asked her if she had a cigarette. "No," she said, "but I have a carnation." --Jennavenda on
East Timor
The Carnation Revolution was a bloodless coup which ended the dictatorial rule of António de Oliveira Salazar and his successor, Marcelo Caetano.
In the early 1970's Portugal was troubled by resource shortages at home and civil wars in its African colonies.
General António de Spínola, sensing that the unrest could not be quelled by force, advocated abandoning colonial rule in the colonies.
Inspired by Spinola's ideas and weary of the current government, a few hundred army officers organized a peaceful overthrow of the government. Led by Francisco da Costa Gomes, Otelo Saraiva do Carvalho, and others, the soldiers took control in late April, just as red carnations appeared in Lisbon flower shops. Soldiers were seen in the streets with red carnations in the muzzles of their tanks and rifles.
At 25 minutes past midnight on the 25th day of April, 1974, Rádio Renascença played José Afonso's banned protest song Grândola, vila morena, the signal for the start of the revolution.
Sources: http://ask.yahoo.com/ask/20010312.html
http://www.cphrc.org.uk