Nothing, necessarily, but it is hard to keep track. You can certainly mark up walls and the like to keep track of where you're going, and to try to get your bearings! But the Horologium is huge and it will take some type to navigate the maze, especially in dim lighting without proper electricity. You may find yourself doubting the shadows in the corner of your eye, and feeling very lost and alone, in your explorations. And that sound is quite offputting...