The Heaven-Piercing Tower was built deep within the Water Curtain Cave Heaven, right beside Sun Wukong's sleeping chamber. Each level of the tower stood ten thousand zhang tall, piercing through the ceiling of the Water Curtain Cave Heaven toward the outside, yet without disturbing the layout of the Cave Heaven. From the outside, the tower did not seem too large, but it employed a spatial formation inside, making its interior immensely spacious. Each level could accommodate ten thousand people at once, divided into challenge areas, cultivation areas, and specific quiet cultivation rooms, like the room where Sun Wukong now rested, which was the most abundant in spiritual energy on the entire fourth floor of the tower.