London (CNN) -- One of the perennial criticisms of Eurovision is that, for a song contest, the compositions are seldom very memorable.
But for the millions who tune in each year, drawn to the promise of outrageous outfits and performances, the contest is as much about spectacle as it is about the music.
For diehard fans, what an artist wears can be a bigger talking point than what they sing. The more misguided an outfit, the better.
In 1997, fan website House of Eurovision founded the "Barbara Dex Awards," an annual prize for the worst dressed artist. The award was named after a Belgian singer who appeared in the 1993 competition wearing an unflattering homemade dress.
"Her song wasn't at all bad, but her performance was overshadowed by that awful self-made dress, and as a result she ended up last," said Edwin van Thillo, who runs the fan site.
Attention-grabbing outfits have always been part of Eurovision's DNA. Germany's 1958 entry Margot Hielscher performed wearing a sash saying "Miss Jukebox," and brandishing vinyl records at the audience. But the past 15 years have seen the costumes reach new heights of flamboyance.
"Visuals have become so much more important since televoting was introduced in 1998," said Sam Broderick, a writer for ESC Nation, one of the most popular Eurovision fan websites.
"Acts only have three minutes to get their song heard and their message across, and they have to compete against 25 other songs to be remembered," he said. "I think that's why so many acts have gimmicks on stage -- and an outrageous costume is just another gimmick. It's all part of the glitz and the glamor of the contest too, and I think that's why people love Eurovision."
But dressing up as a bird, butterfly or robot doesn't guarantee success. Many of the acts featured in our gallery finished near the bottom of the table, or failed to progress past the semi-finals.
"A terrible outfit can destroy any chances a song may have had," said Broderick.
"I remember watching rehearsals in Oslo in 2010 when the Maltese entrant Thea Garrett came on stage with her backing dancer dressed as a massive bird. The whole press center was in howls of laughter," he said. "It was quite highly regarded before then, but I really think that big bird put paid to the song's chances."