Watch the World Cup with the sound on.
Serious. Just listen. All you'll hear is a humming. No chants.
Just a hum. A long, tuneless, pitchless, heartless, gutless, lifeless hum.
It comes from a vuvuzela, which is a longish plastic horn the South Africans blow on.
Fifa tried to ban them, apparently, but that didn't fly.
Good article on them here.