I'm looking for a movieTwo kids a boy a girl about 12 year old or so go to a construction site and find a crystal ball, did bring it home and turns out there's people inside it and the president of like the society is this really old dude in the entire mo

I’m looking for a movie about,
Two kids a boy a girl about 12 year old or so go to a construction site and find a crystal ball, did bring it home and turns out there’s people inside it and the president of like the society is this really old dude in the entire movie there’s like these bad guys or aliens or something trying to chase them down to get the crystal ball

Solarbabies (1986)?
Not that they were in a construction site per se, but it did look like one.

The Shrunken City?