So for the uninitiated, Eurovision is a song contest. Countries that are in Europe, along with some former Soviet republics and Australia, submit entries - the only criterias are the song length must be no longer than 3:30 (I think) and the maximum number of people on the stage is 6 for each country. Also, countries are not supposed to submit songs with a political message.
Six entries (the Big 5 - Italy, Great Britain, Spain, Germany and France), along with last year's winner (Switzerland), automatically qualify for the Grand Final on Saturday. The remaining countries qualify for the finals in one of two semi-finals that take place on Tuesday and Thursday. Russia and Belarus are not allowed to participate due to the war in Ukraine.
In the semi-finals, songs are voted on by the viewing public. Yes, Americans can vote (but only in the final). You just have to pay for up to 20 votes. The top 10 vote getters in each semi advance to the Grand Final. Only countries that in that semi-final can vote. The Big 5 and Switzerland also perform during the semis and their citizens can vote during that semifinal.
On Saturday, 26 nations will compete for the Eurovision title. Probably the most famous winner is Abba's "Waterloo" in the 1970s. The winning nation gets to host the next year. It's a huge specticle and is basically the most watched program in Europe. Literally, it's their Super Bowl. Think American Idol, but A LOT bigger.
2024 winner - Switzerland, "The Code"
2023 winner - Sweden, "Tattoo"
2022 winner - Ukraine, "Stefania"