Congratulations: 50 Years of the Eurovision Song Contest was a television programme organized by the European Broadcasting Union (EBU) to commemorate the Eurovision Song Contest's fiftieth anniversary and to determine the Contest's most popular entrant of its fifty years. It took place at Forum, Copenhagen on 22 October 2005. The host broadcaster was Danmarks Radio (DR). Fourteen songs from the Contest's first half-century, chosen through an internet poll and by a jury, contested the event. Thirty-one EBU-member countries broadcast the concert (although the United Kingdom, Italy and France did not) and televoting and juries in these countries decided the winner. 2.5 million votes were cast in total on the night.
The event was hosted by Katrina Leskanich and Renārs Kaupers. The event was won by Swedish group ABBA, performing "Waterloo"; the band had originally won the Contest for Sweden in 1974.
To coincide with the event, the EBU released two CDs featuring Eurovision songs from the previous fifty years. Two DVDs with original Eurovision performances of these songs were also released.
In June 2004, the European Broadcasting Union announced that it was to hold a concert to celebrate fifty years of the Eurovision Song Contest. The event was to be held on 16 October 2005 at the Royal Albert Hall in London, England. The BBC was to host the concert. The Royal Albert Hall was reportedly unavailable, so in August 2004 the EBU announced that DR would stage the event instead. Eurovision Song Contest supervisor Svante Stockselius said that Denmark's previous experience of hosting Eurovision events (the 2001 Contest and the first Junior Eurovision Song Contest) were influential in the Union's choice. Former Eurovision winner Dana International, who appeared at the event, later went to suggest that the reason behind the change of host country was also due to the fact that the BBC wanted to present the show "with humour" as thought to poke fun at the Contest, an idea that proved to be less popular with the EBU. The event was codenamed Extravaganza. On 25 October 2004 Copenhagen was confirmed as the host city for the event, which was now scheduled to take place on 22 October 2005. In May 2005 Congratulations was confirmed as the official name of the concert. A month later DR announced that Forum Copenhagen would host the programme. On 9 September 2005 DR announced that Katrina Leskanich and Renārs Kaupers would present the concert. Leskanich was the lead singer of Katrina and The Waves, who won the Contest for the United Kingdom in 1997. Kaupers is the lead singer of Latvian group Brainstorm, who represented Latvia on its debut in the Contest in 2000.
Fourteen songs would compete in Congratulations. In May 2005 the EBU opened a poll on its website to decide ten songs that would contest the event. Voters chose their two favorite songs from each of five decades: 1956 to 1965, 1966 to 1975, 1976 to 1985, 1986 to 1995 and 1996 to 2005. The remaining four songs would be selected by the EBU's Reference Group. On 16 June 2005 the fourteen chosen songs were announced, although no indication was given as to which had been chosen online and which by the Reference Group.

Both juries and televoting were used at Congratulations; both having an equal influence over the vote. In the first round of voting, the number of songs was reduced to five. Each country awarded points from one to eight, then ten and finally twelve for their ten most popular songs. Unlike in the Contest proper, viewers were allowed to vote for songs which had represented their country. The top five songs were then subjected to another round of voting, where only six points and above were awarded. The voting was conducted in private, and the results were not announced until after the show. The song with the most points in the second round was the winner.

First Round

Second Round