Giantess Nina is dancing on the high-altitude-plank road, which is built hovering over the city below by 150 meters high above the ground. The purpose is to let all giantesses visit and play with the whole city without ruining anything or any life. There're openings on some glass blocks for adjusting air in the city or some interactions between tiny people and giantesses. And some bigger openings are for skyscrapers higher than 150 meters to stick out to the sky.