The Carnation Revolution (Revolução dos Cravos), is celebrated on 25th of April each year. (vinte e cinco de Abril).

There was initially a military coup in Lisbon, Portugal, on 25 April 1974 which overthrew the regime of the Estado Novo. The revolution started as a military coup organized by the Armed Forces Movement composed of military officers who opposed the regime, but the movement was soon expanded with the addition of the unanticipated and popular campaign of civil resistance. This movement would lead to the fall of the Estado Novo and the withdrawal of Portugal from its African colonies and changed the Portuguese political system from an authoritarian dictatorship to a democracy. 

The name "Carnation Revolution" was given after the event, as almost no shots were fired and when the population took to the streets to celebrate the end of the dictatorship, red carnations were put into the muzzles of the soldiers guns and worn on uniforms. It has been said that a flower seller at the end of the bridge the army crossed passed the carnations to the solders as they passed her. The bridge we now know as the 25th April Bridge.

The revolution was led by General Antonio Spinola and other prominent civilian and military figures. In just a few hours, General Spinola received the surrender of the overthrown Prime Minister, Marcelo Caetano, who was forced into exile in Brazil. Ceatano had taken over as Prime Minister from Salazar in 1968, after Salazar suffered a stroke. President Américo Tomás and removed Salazar and put Caetano in place but Salazar still beleived he was Prime Minister until his death in 1970. Some social changes took place but the country was heavy involved in wars in 3 of its colonies and financially stretched. It was still a dictatorship until after the Carnation Revolution, when finaly free elections took place and a democracy was formed. Tomás was also exiled in Brazil.

In Portugal, 25 April is a national holiday, known as Freedom Day (Dia da Liberdade), there are many events around the country to celebrate the event, but mainly in Lisbon (where it took place), Peniche (where many political prisoners were liberated), and Caldas da Rainha (where, it is believed the initial planning of the revolution took place at the Army Sergents College).

There are also big events in Oporto is most many other cities and in recent years the day is also used for politcal demonstrations in Lisbon.