Patty and Mildred Hill are the most famous composers you've never heard of.
They came up with "Happy Birthday to You " in an effort to make something all children could easily sing. They ended up with a tune the whole world loved.
"Happy Birthday to You " has been sung to presidents and kings, on big stages and in outer space. And it all started in a kindergarten classroom with a teacher coaxing her children to sing an easy tune all together.