In this episode of "Housed in Tradition" series, we're still in China's largest megacity, Shanghai, with a population of over 20 million. Its advanced public transportation system keeps it running smoothly, the metro in particular. It passes through the historical downtown areas and connects the city's outskirts. Let's follow CGTN's Qi Jie and take the subway to find out how urban planners care about those historical structures above the routes.