Since 1974 “Freedom Day” is celebrated in Portugal — April 25 – as a national holiday to mark the bloodless military coup, supported by the civilian population, bringing democracy and civil liberties to the Portuguese people.
After almost five decades of dictatorship (1937-1974), the Carnation Revolution, ended the Estado Novo regime, the longest dictatorship in Europe, changing the Portuguese political system from an authoritarian dictatorship to a democracy.
The revolution was undertaken by the Armed Forces Movement (MFA) led by General Antonio Spinola and other prominent civilian and army figures. In a matter of hours, General Spinola received the surrender of overthrown Prime Minister Marcelo Caetano who was forced into exile in Brazil.
Spinola took charge of a Provisional Government which promised to restore civil liberties and hold democratic general elections. Hundreds of political prisoners were released.
In 1974, more than half of Portugal’s government budget was spent with its armed forces engaged in wars in three of Portugal’s African colonies. The new regime implemented a swift decolonization program granting independence to Guinea-Bissau, Mozambique, Cape Verde Islands, Sao Tome and Principe, and Angola.
Over the course of the next decade a stable two party system was established. Soon after, in 1980, the archipelagos of Madeira and the Azores became autonomous regions to enjoy self-government.
Under the constitution of 1976, which established a parliamentary republic, Portugal has been governed by a constitutional democracy with a president, a prime minister, and a parliament elected in multiparty elections. The Portuguese constitution was amended in 1982, 1989, 1992, and 1997. More @ https://en.wikipedia.org/wiki/Carnation_Revolution