Quilapayún

But how did a Latin song become so powerful and spread worldwide even before the internet? Well, that's the power of youth movement.

Composer Sergio Ortega wrote the song with the band Quilapayun in Santiago in 1973, months before the coup against Chile's socialist president Salvador Allende.

On the morning of September 11, as the armed forces moved against him, Radio Magallanes played it minutes before Allende's final speech.

By the end of that day, Allende was dead and Augusto Pinochet's dictatorship had begun.

Quilapayun went into exile in France and in Tijimani, another band that recorded the song, went into exile in Italy.

Both carried the song to concert stages across Europe.

The team behind the documentary IMNO has counted about 150 recordings in 25 languages.