What's that ONE spanish song that if someone starts singing it (or opens the song), everyone sings along?

I would love to learn more about spanish culture so i thought this question would be fun to ask to know more i guess, lol but im also curious about it! and i know it's probably different between generations but ill still ask. It's that one song that every single person knows, young/old/whatever, they'll sing it.

For example Michael Jackson, everyone knows at least ONE song from him, no matter what year you were born in.