Magic tunnel

is where you can go for a long walk underground. Too bad after half an hour you start getting really hungry, and then you start wondering: how is it that I can see in here. That's magic tunnel, which you are still walking through, and now you are really hungry, and the question bears asking: when will this thing ever end. And you keep going along, and it can never be boring in magical tunnel because every step is deeper in, and further along, and greater discovery.