The hit tune Waterloo by Swedish pop group Abba has been voted the best song in the history of the Eurovision Song Contest.
Sweden's Abba won a public vote for the best song with 1974's Waterloo
Viewers in 31 countries across Europe watched a special show in Copenhagen, Denmark, to celebrate the annual event's 50th birthday.
Former Eurovision acts who attended the Congratulations party included Dana International and Bucks Fizz.
The public voted on a shortlist of 14 - not all former winners of the contest.
Original video recordings of the chosen songs, some in black and white, were shown in the course of the show.
Abba did not attend but some previous contestants - including Ireland's Johnny Logan, whose song Hold Me Now was voted third best - performed live.
Second place went to Italy's Domenico Modugno for his 1958 tune Nel blu, dipinto di blu, better known as Volare.
TOP FIVE EUROVISION SONGS
Waterloo - Abba, Sweden, 1974
Nel blu, di pinto di blu (Volare) - Domenico Modugno, Italy, 1958
Hold me now - Johnny Logan, Ireland, 1987
My Number One - Helena Paparizou, Greece, 2005
Save your kisses for me - Brotherhood of Man, UK, 1976
Other contenders included Congratulations by the UK's Cliff Richard and Ne partez pas sans moi by CÚline Dion, for Switzerland.
Ten of the songs were chosen by fans from all over Europe and the other four were a wildcard from the Eurovision Song Contest Reference Group.
Former UK winners Brotherhood of Man, Spanish group Mocedades and Turkish Sertab Erener were among the shortlisted performers to play live.
Other Eurovision stars who attended included Sandra Kim and the Olsen Brothers, as well as the first winner of the contest, Lys Assia, who represented the contest's host nation, Switzerland, with her song Refrain.