Off the bustling streets, people go into the underground, taking a galloping subway. Many of the people who work hard in the city go together towards different exits through the pitch-dark and winding tunnel. In the eyes of travelers, the subway is the best means to know about a city. It is fast and convenient, and what’s more, you will feelthe somewhat mysterious crossing of space and time. You will always involuntarily predict the sceneries greeting you behind those familiar or unfamiliar platforms.