I remember seeing part of a movie a long time ago, but the only thing I remember about it was two boys find the entrance to an underground tunnel and go in. The inside of the tunnel was blue almost like there was lighting in the sides of it. It was square and went on as far as you could see. After walking in to it for a long long time it still seemed to go on forever. I was maybe 6 when I saw this so I have no clue about the rest of the movie but am curious what it was. Anyone have any idea what this was called?

Could it possibly be "The Gate" 1987
The Gate (1987) (http://www.imdb.com/title/tt0093075/)