Backstage prior to kicking off todays rehearsal some of the artists spoke to Eurovision.tv.
Poland, Albania & Switzerland impressions
Poland's Magdalena Tul said "The stage dress is so heavy. I can't move as much as without it, but I will try, and I think it will be okay."
Albania's Aurela Gaçe told "The song has something from Albania included. We all breathe the same in this big world, but we still grew up in different countries and have our small differences that make us individual."
Anna Rossinelli of Switzerland said "Of course the Swiss people are interested, but they are also a little bit sad, since we haven't got to the Final since 2006. I hope it's going to change this year!"
Georgia, Iceland, Hungary and Greece reactions
Georgia are represented by Eldrine, they said "We're using fireworks with big effects. This is to give our performance more power, it will breathe energy to the audience."
Iceland's Sjonni's Friends said "The message is to seize the day. We're all such good friends and like to be together, so it's not hard to prepare for the stage."
Kati Wolf from Hungary said "I think it's best to go 100% on the rehearsals, you have to be ready for the broadcast."
Loucas Yiorkas from Greece was the last artist to speak backstage and said "We're having break dance and traditional Greek dance, because the song is a combination of these two kinds of music."
And now for the show
For both Semi-Final shows and the Final, there will be three presenters. They are entertainer Stefan Raab, news anchor Judith Rakers and comedienne Anke Engelke.
The presenters explain the voting rules of the First Semi-Final for the audience, and explain that 10 countries will qualify from the 19 participants.
From Poland to Armenia
Poland are first up, Magdalena Tul's Jestem is well choreographed and she wears a heavy white dress with silver elements. The whole group are dressed in white, and it is an energetic opener to proceedings.
Stella Mwangi is next for Norway in her gold outfit. The backing dancers and vocalists are in red as they dance the Haba Haba. Stella wears huge disc shaped gold earrings and red African style bangles on her wrists.
Albania next, Aurela Gaçe is wearing a cream and white dress, and although has worn many hairstyles whilst here in Germany, has her hair tied back today. She delivers a very strong and competent vocal performance of Feel The Passion.
Armenia's Emmy enters the stage sat in a huge boxing glove and is dressed in a red boxers cape which she throws off before the first chorus of Boom Boom. Emmy's dress is white with a Lonsdale belt across her waist. The dancers trap Emmy in a boxing ring part way through the song. It all makes for a very impressive visual effect.
Turkey through to Switzerland
It's green, gold and black costumes for the Turkish group Yüksek Sadakat. The stage for Live It Up set is dark with a lot of flashing spotlights and a female dancer is entrapped within a globe on stage, and then reveals herself with golden wings at the end. She happens to be the same cybergirl from last year's Turkish entry.
Now there is a break where some footage is shown from the Mayor's official opening reception where hosts Stefan and Anke are making participants sing German folk songs.
Back to the songs, and the bubbly Nina from Serbia is next. Čaroban has a very late 1960's retro feel to it, not only in the way the music sounds, but also the way the stage is set up and the contrast of colour within the costumes. Nina smiles throughout and the performance has the feel good factor.
Alexej Vorobjov begins the opening of the Russian entry Get You in the Russian language. Alexej wears a black leather jacket and white shirt, and the choreography between himself and his backing dancers is very slick and polished. The Russian team use another LED wall. The production is very impressive.
Switzerland's Anna Rossinelli has a sparkling elegant red dress, In Love For A While is a dreamy ballad and the performance is all about the music with a cellist and guitarist on stage with Anna. The simple effect is something Switzerland are hoping will help them qualify for the Final.
Georgia to San Marino
Eldrine from Georgia are wearing black costumes, some of them with green, yellow and red frills for their rock number One More Day. Lead singer Sophio is immaculate vocally and the stage set is very rock oriented.
Finland's Paradise Oskar next, with singer Axel standing playing his guitar against a dark backdrop with a rising image of planet Earth. Da Da Dam is the first song where only one person is on stage. Although simple, the staging is very effective and fits perfectly the message of the song.
One of the most outgoing characters in this year's contest is Glen Vella from Malta. Glen wears jeans with a white t-shirt and grey jacket for his performance of One Life. He has two male backing dancers strutting their stuff and three female backing vocalists. Part of the preview video appears on the LED screens. Glen gives a strong vocal performance.
Senit sings only the second ever entry in the history of the Eurovision Song Contest for San Marino, Stand By. Senit is wearing a silver long dress and has a full band on stage with her. A good rehearsal for San Marino.
Croatia to Portugal
Croatia's Daria has the most ambitious stage act so far. She changes from a black dress, to a pink dress, and ends in a silver one!. She is also the first to use the catwalk as she waves to the crowd. Celebrate is an uptempo and cheerful song, and is bound to go down well with a full audience in the arena.
Sjonni's Friends sing Coming Home for Iceland. The guys are all wearing grey waistcoats, white shirts and jeans. There is a distinct country feel to the song, and the guys harmonise very well together and deliver a solid performance.
Another break now, where Judith Rakers makes a report from the green room chatting to a number of the contestants.
Hungary next, Kati Wolf is dressed in a blue dress with a huge sleeve on her left arm. There are three dancers with Kati, and two female backing singers. They have outfits which illuminate during the second verse of What About My Dreams.
Homens Da Luta are Portugal's act, Luta É Alegria is the Portuguese entry. The group all hold banners in many different languages, all saying the same thing The Struggle Is Joy, the literal translation of the song title. It is a very colourful set and performance.
The final three songs
The set is dark blue for the Lithuanian song C'est Ma Vie. Evelina Sašenko is joined by a pianist on stage. She uses sign language during the second verse. Evelina sells the song very well and nails it vocally.
Azerbaijan are the penultimate country to rehearse. Ell & Nikki sing Running Scared. They are dressed in white. They have four female backing vocalists. It is a classy routine and performance, and went down well with the crowd.
Finally, Greece take to the stage with Loucas Yiorkas & Stereo Mike. Watch My Dance is the Greek entry, an interesting mix of modern and old in both the music and dancing. Rap, hip hop and breakdancing from the modern side and traditional Greek singing and dancing from the past. A very powerful end to the Semi-Final.