Waterloo

Andersson, Ulvaeus and Anderson wrote it for the 1974 Swedish Eurovision heat. The group also considered Hasta Mañana, but chose Waterloo because it gave both women equal weight as lead singers. Janne Schaffer came up with the main guitar and bass parts, and Tretow's layered production followed the wall-of-sound approach. ABBA named Wizzard's See My Baby Jive as a major influence. The Swedish version won the heat on 9 February 1974 with 302 points to the runner-up's 211, and German and French versions were recorded in March and April.

On 6 April 1974 the English version won the Eurovision Song Contest at The Dome in Brighton, performed eighth, with 24 points, six clear of Italy's Gigliola Cinquetti. Sven-Olof Walldoff conducted in a Napoleon costume. It was the first winning entry in a language other than that of its home country. The British jury gave it no points, and Ulvaeus suggested 47 years later that the UK saw ABBA as the biggest threat to Olivia Newton-John, the favourite to win. The single reached number one in the UK, where it stayed for two weeks, and number six in the United States. In 2005, at the contest's 50th anniversary show, it was chosen as the best song in Eurovision history, and Billboard ranked it ninth in its 2017 list of the 15 best ABBA songs.

It appears in 132 of the 273 logged ABBA setlists that list songs, the earliest dated 9 February 1974 and the latest 27 March 1980 at the Nippon Budokan in Tokyo. Many of these entries are television appearances.