Balcony introduction: The "Dragon`s Belly" on the roof is the attic, which is the inside of the dragon's spine. The main color of the interior is tooth white, and the use of exquisite catenary arches fully reflects Gaudi's naturalistic tendency. This structure imitates the giant reptile dinosaur that once lived in the Mesozoic era. The center of gravity of the dinosaur's huge body, long neck and thick tail is at the waist. The weight of the body is transferred to the thick limbs through the body's center of gravity. The upper part of the body is like an arch bridge, an ideal structural shape that can withstand huge loads. It also uses less material, is strong and resistant to pressure, and has a beautiful appearance.