It was forty years ago an unknown group took to the stage at The Dome in Brighton and thanks to that appearance were to become one of the best known and most successful groups ever.
They are of course ABBA who won Eurovision.
Well this weekend fans travelled to the groups home City and one of the group made a very rare appearance.
Tonight other members of the band will be in London for a special party.
Mike Pearse was at the special weekend event and has been meeting some of ABBA's army of local fans.
Arguably one of the most popular bands of the century, ABBA won the Eurovision contest held in Brighton in 1974.
The Swedish pop group sang 'Waterloo' to ensure victory 40 years ago.
Now, an exhibition is being held in Stockholm to commemorate their success, where visitors can get up close and personal with the band's outfits, instruments and even a ticket for the Dome.
40 years to the day that ABBA won Eurovision at Brighton memories of that famous night have gone on display in Stockholm, the home city of the band.
The costumes the group wore on stage, the guitar they used, the medal they won and even a ticket for the show at The Dome are among special exhibits.
Later a special concert will be held at the ABBA museum to mark the anniversary. Events are also being held in Brighton.