I found a hole through the bottom of the world. If you start at the stair way going under ground that has some glass over it next to the bakery (it is labeled) and follow the signs, you will get there within about 2 mins. Fall through and wait for the world plane to disappear. Push t and type /home. It will respawn and for roughly 5seconds or so you can see every tunnel we've made underground through the ground. It is neat.