Fifty years ago today, ABBA's song "Fernando" debuted on the Billboard Hot 100 in the United States, eventually peaking at number 13 in November of that year. Though other ABBA songs have charted higher, "Fernando" is still regarded as one of the band's finest moments, and its creation highlights songwriter Björn Ulvaeus's sharp instincts for turning a decent track into a genuine hit.

The song began life as a Swedish-language solo track by Anni-Frid Lyngstad, a simple, sentimental love song about comforting a heartbroken friend. When ABBA decided to rework it for international release, they switched the lyrics to English for the UK and US markets, but Ulvaeus felt the original words were too plain. He rewrote them entirely, reimagining the song from the perspective of two ageing comrades reminiscing about a fictional Mexican guerrilla war, transforming a straightforward love song into a far more evocative and enduring hit.