400 children went to the summit. They were asked to vote for the three best ways to improve the world for young people.
They picked from a list of 10 options.
Two teenagers were chosen to present the results of the vote. Gabriela from Bolivia who is 13 and 17-year-old Audrey from Monaco were picked.
They spoke the meeting of world leaders. It was the first time young people had made a speech to the General Assembly of the UN.