Freedom Day on 25 April is a national holiday in Portugal, with official commemorations.
It celebrates the 1974 Revolution that ended the dictatorship and started democracy.
Known as the Carnation Revolution, this was a virtually bloodless, leftist, military-led coup.
It began on 25 April 1974, in Lisbon and transformed the Portuguese regime from an authoritarian dictatorship to a democracy.
It followed a long period of social change and power struggles between the left and right wing political forces.
Whilst the government forces killed four people before surrendering, the revolution was somewhat unusual in that the revolutionaries didn't resort to violence to achieve their goals. The population, holding red carnations, convinced the army not to resist and the soldiers swapped their bullets for flowers.
The revolution marked end of the longest authoritarian regime in Western Europe.