People all over the UK have been voting in this year's crucial general election - and it's closer than it's been for decades.
Even the experts aren't sure which party is going to win, as the big three - Labour, Conservatives and the Liberal Democrats - are all doing well.
The leader of the party that wins the most seats will be prime minister for the next five years.
This means that party will rule on important issues like money and jobs.
But there are fears the next government won't have much power. This is because there could be what's called a 'hung parliament'.
People voting in a booth
This means that even though one party has won more seats in the House of Commons than anyone else - they don't have a big enough majority to get all their laws passed easily.
Often this means parties who are normally against each other have to join forces to make laws - and this can means lots of arguments and delays in getting things done.
Whatever happens, Thursday and Friday will be important days for UK politics, with millions of people waiting to see who will become the next prime minister.