The Carnation Revolution or Portoguese Revolution of 1974 refers to a military coup and the resulting unrest which brought down the fascist regime in Portugal and led to numerous progressive reforms and nearly created self-management in industry. Occurring on the 25th of April, 1974, the revolution was part of a wider chain of global revolts against authoritarian governments and cultures.
US Interference
An excerpt from William Blum's book Rogue State provides the best summary:
A bloodless military coup in 1974 brought down the US-supported 48-year fascist regime that was the world's only remaining colonial power. This was followed by a program centered on nationalization of major industries, workers' control, a minimum wage, land reform and other progressive measures. Washington and multinational officials who were on the board of directors of the planet were concerned. Destabilization became the order of the day: covert actions; attacks in the US press; subverting trade unions; subsidizing opposition media; economic sabotage through international credit and commerce; heavy financing of selected candidates in elections; a US cut-off of Portugal from certain military and nuclear information commonly available to NATO members; NATO naval and air exercises off the Portuguese coast, with 19 NATO warships moored in Lisbon’s harbor, regarded by most Portuguese as an attempt to intimidate the provisional government. The Portuguese revolution was doomed. The CIA-financed candidates took and retained power for years.