The project cleverly utilized the unused space on the roof of the building to build a professional-grade American football sports arena on the roof, covering an area of about 2,500 square meters as well as a basketball arena of about 1,500 square meters. the project was completed in only 25 days from installation to completion. The curved top makes the space more streamlined in addition to the use of heat insulation materials, which can keep the whole indoor space warm in winter and cool in summer. Considering the daily operation of the football arena and the experience of visitors, a clear division was also made for the functional areas, including reception, locker room, recreation area, office, balcony, etc., transforming the original unused space into a multi-functional and high income generating asset.