Eurovision performers from 25 countries on Friday went through a full dress rehearsal for the grand final, while Spain's prime minister defended the country's boycott of this year's event over Israel's participation. This year in Vienna marks the 70th edition of the Eurovision Song Contest, which despite the razzmatazz rarely escapes the politics in the background. Eurovision is the world's biggest live televised music spectacle, typically reaching more than 150 million viewers, and Saturday's final at the Wiener Stadthalle is set to be no exception.