Blowin' in the Wind
In the late 1960s, some entries from the dictatorial Iberian regimes featured distinct metaphors for freedom, disguised as love songs to avoid censorship. While Portugal was still the colonial power in Africa's Angola, local singer Eduardo Nascimento sang "The Wind's Changed." (see what he did there?).
In 1974, the year Abba won for "Waterloo", the Portuguese entry would go on to become part of the country's history. Less than a month after the contest, as the left-leaning military plotted to overthrow Portugal's dictatorial regime then led by Marcelo Caetano, the Generals decided to broadcast a coded signal over Catholic Radio Renascenca to indicate the start of the uprising. That signal, Paulo de Carvalho's "And After The Goodbye" started the Carnation Revolution on April 25, 1974. While many Eurovision entries have sparked protests through the years, this remains the only song to have actually started a revolution.