Kids movies - sci fictionish late 80' early 90?

so i dont remember much but there is a magical being and there is/are a kid/kids that walk some tunnels or something and at the end, the kid/s end up on the other side if the country after only walking the tunnels for a while and he/they call home and ask for the parents to take him/them back home and they are like whee are you? and they found out it is on the othe side of the country and go How did you get there????