Introduction to Longwan Rainbow: The sea area where Qingdao Yinhai International Yacht Club Pier is located is called Laolong Bay. Above the entrance to the eastern end of the harbor, the world's first mechanically opening and closing rainbow bridge was erected. This rainbow bridge with a steel tube structure is designed based on the "Millennium Bridge" on the River Tyne in Newcastle, England. It is 60 meters long and 2 meters wide.