The annual song competition is the moment when people of various cultures discard their differences and celebrate what they share in common: a love of pop music.

Eurovision means different things to different people, varying from the serious to the sublime –and the plain kooky– but it embraces it all.

At its heart is a highly competitive, unpredictable contest between songwriters, but it is frequently upstaged by performance. Singer, dancer, musical instrument, fashion, choreography and gimmick frequently overwhelm composition, melody and lyric.

So many of us know ABBA won the contest in 1974 with Waterloo, but how many know the writers of the song? OK, bad example, everybody knows Benny and Bjorn (Stig Anderson was the third composer). But few would be able to name the composers of 2010's winning song, Satellite sung by Germany's Lena. It was composed by American Julie Frost, who co-wrote Black Eyed Peas' Just Can't Get Enough, and Dane John Gordon.

These days we are drawn to the showbiz of Eurovision and there's certainly nothing wrong with that. But it began as a much purer contest when it was the brainchild of Marcel Bezençon, who was the director of the European Broadcasting Union. The EBU consists of public broadcasters and in 1955 they met to devise a joint-broadcasting event.

Eurovision was unashamedly inspired by Italy's San Remo Music Festival, which began in 1951 and continues to this day.

The very first Eurovision Song Contest was staged in the picturesque lakeside city of Lugano, Switzerland, with seven participants: Luxembourg, the Netherlands, Belgium, West Germany, Italy, France and Switzerland itself. It was won by the Swiss entrant, Lys Assia with Refrain who, in her winning encore performance, forgot the words and sang "la la la la" – it set a precedent for car-crash moments for decades to come.

In its 55-year history Eurovision has become a juggernaut of television and music.

More than 1100 songs have featured in the contest. It is watched by 125 million viewers in such far flung places as Hong Kong, Canada and Egypt. Having aired every year since 1956 it is also one of the world's longest running television shows. Parties gather around television sets to watch the contest unfold. Due to its live broadcast in Europe, the show captures a continent's imagination because everyone watches and votes for the songs at the same time.

Eurovision has the capacity to ignite music careers. It was ABBA's 1974 Waterloo appearance that became their breakthrough moment, despite failing to qualify for Sweden in 1973 with Ring Ring.

But there have been numerous success stories (and many since forgotten) from Eurovision.

Celine Dion won in 1988 when she represented Switzerland and wowed audiences with her vocal dexterity, although true success would continue to elude her until she recorded Beauty & the Beast with Peabo Bryson in 1991.

It has welcomed such artists as Cliff Richard, Olivia Newton-John, Bucks Fizz, Nana Mouskouri, Gina G, Katrina and the Waves, Michael Ball, t.A.T.u and even Sir Andrew Lloyd Webber (as an accompanist).

Australian-born Johnny Logan (from Frankston, in fact) is still Eurovision's most successful entrant.

Logan first won Eurovision representing Ireland in 1980 with the song What's Another Year? In 1987 he returned to win with his own composition, the ballad Hold Me Now which went on to become his defining song. In 1992 he wrote the winning song, again for Ireland, Why Me? performed by Linda Martin (both had previously contested in 1984 and finished second).

But Eurovision is also about politics.

There have been fierce debates over the lyrics of songs. Georgia's We Don't Wanna Put In was banned from entry in the 2009 Moscow event because it was seen as a direct criticism of Russian Prime Minister Vladimir Putin.

In 1968 Cliff Richard lost the contest in London by just one point. It wasn't until 2008 that it emerged Spanish dictator Francisco Franco had effectively bought votes because he wanted Spain to host the next contest. Staging the contest has also seen small nations transform themselves.

Claims of bloc-voting are the stuff of legend within Eurovision, notably since the demise of communism in Eastern Europe. In recent years the EBU has sought to diminish the ability of bloc-voting with a more stringent system of semi finals, and it seems to be working.

Then there are the social breakthroughs of Eurovision. Israel's Dana International turned heads when she won in 1998 with the thumping Diva. Her other claim to fame was being transgender.

Eurovision has it all, transcending music, politics, social and cultural boundaries. Yet despite all these, there is nothing that connects so innately, so powerfully as a singer and their song.

There are 43 of them in 2011 – which one will it be this time?

The History of Eurovision, airs Friday, May 6 and Friday, May 13 at 7.30pm, SBS ONE.