Eurovision Song Contest is a very big event and like with all big events, there are things that go wrong from time to time. Fortunately, most of them don't ever get to be seen by the public.
It's because at Europe's favourite TV show the key is to rehearse everything until there are no more mistakes and room for errors.
For this, all contestants have their individual rehearsals as well as the three Dress rehearsals for each show and several other for the interval acts, hosts and announcing the votes. Time enough to make sure everything works!
For example, in the first rehearsal Eric Saade attended, the famous glass box wall did not break and he had to open the door and just walk out from the box.
However, it was rehearsed one extra time to be sure it would in the live shows. And so it did and helped Eric to regain Swedish glory by placing third in Düsseldorf.
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It's still a live show
All systems at the Eurovision Song Contest are always backed up and tested many many times but even then there's a tiny chance of things going wrong - after all, it's still a live show!
During the first Semi-Final in 2011, one of the most unlikely events occurred - there was a problem with the so-called multi channel audio connection, which was not working correctly. And this meant, there was no commentary audio in a few countries...
However, all was fixed as soon as possible and it went fine for the second Semi-Final and the Grand Final, so all's well that ends well.
Our special moment
We at Eurovision.tv work at the Eurovision Song Contest for about 2,5 weeks during the event in May. And of course, we also have our 'special moments' when not everything goes as planned.
The first time our team got to the Düsseldorf Arena, for the first individual country rehearsal, everyone was so very excited.
Like always, there's a special table equipped with electricity and internet connection for our video crew to work at really close to the stage.
Remember the confetti Stella Mwangi used in her act of Haba Haba? We sure do - during her first rehearsal it all the shiny pieces landed on our table! That was probably the closest we ever got to look like Verka Serduchka...