Wonderful Copenhagen?

I've tried googling it, but it seems like no one knows why they are shouting it all the time. Maybe it's some sort of honour to "Terkel i Knibe". Who knows?

- To the fallen heroes

It might be a reference to Danny Kaye's classic song "Wonderful Copenhagen", but I vaguely remember hearing the phrase uttered by wealthy americans in older movies when referencing Copenhagen as the ultimate vacation destination.

Could it possibly be some kind of commercial campaign slogan from the 30s-40s?

It's the new neighbor that starts saying it in the film, and it's later on revealed that Copenhagen is where he studied medicine.