The interval act at the 1990 Eurovision Song Contest in Zagreb, then-Yugoslavia; the film "Yugoslav Changes".
For their interval act, Yugoslavia chose a film about life in Yugoslavia. This short 'documentary' couldn't have come at a better time, as it showed normal life in the country before it broke up into war just a couple of years later. This is as far as I know the contest's longer interval act, almost 10 minutes in length, but it's very interesting nonetheless and well put together.
Incidentally, 'Zagreb' means 'that which is over the hill' in Croatian.
