Traversing a class hierarchy?

Hi, I’m currently working on a tower defense game and am in kind of an odd situation. I’ve programmed it in such a way that a large class hierarchy is in place. It’s like this

StartScreen class —> BaseLevel class —> GUI class —> TowerPlacer class(towers are stored in an array in this class) ----> etc.

My problem is that i need to access an array in BaseLevel from my GUI class, is there any fancy trick for doing this? or have i screwed myself over. I could probably come up with a workaround for my specific problem but i feel like i’ve done something wrong in building my program like this. Thanks!