What's a song that everyone in Switzerland knows?

Every country has that one song that everyone (or almost everyone) in it knows the words to that isn't the national anthem. In Australia it would be Waltzing Matilda, in Italy it'd be Bella Ciao, Zimbabwe has It's A Long Way To Mukumbura, the Americans have West Virgina Country Roads, the Germans have 99 Luftballons (or Schrei Nach Liebe), what would the equivalent be in Switzerland? I suppose there could be more than one since we have 4 official languages.

Edit: Wow this post blew up, thanks for the replies everyone. It looks like I have some homework now since I've never heard half of these songs.