80’s Movie with kids in different world

Hello, I’m having trouble remembering the name of a movie from the 80’s. Here’s what I remember:

1: Kids travel through fog/mist to another dimension/world

2: They encounter some other civilization, where they through people (possible criminals?) into a white hole.

3: I was asking my sister about this movie to see if she remembered and she swears the kids parents were part of a circus or something like that (hoping we’re not talking about two different movies).

Thanks!

Need more clues, mate.

Early guesses would be 'The Neverending Story' or 'Time Bandits'.

If not, then more clues would be nice.

Time Bandits sounds the closest because I think there are scenes with fog or mist at times. Plenty of different time zones involved as well which might make you think of a different civilization, as well as portals that people go through.

Phantasm

In MIRRORMASK the heroine travels to a fantasy world, and her parents in this world run a circus (which she is a part of). But that film came out in 2005.

Some searching online suggests it may be THE GREAT LAND OF SMALL (1986)

It was The Great Land of Small. Thank you everyone for your responses.