Looping around the city, Line 4 is the only circular system of tracks that rings Shanghai. There is the Inner Ring, which starts at Yishan Road and circles around to Shanghai Railway Station, then to Century Avenue and once again makes it way back to Yishan. The Outer Ringer also starts at Yishan but travels the other way around towards Century Avenue first, then Shanghai Railway Station and back again to Yishan. Look for the two loops marked in a deep purple color on metro maps. The 33 kilometers of tracks include stops at 26 stations like the Shanghai Indoor Stadium, Nanpu Bridge, and Zhongshan Park.
Transfer to Line 1 at Shanghai Indoor Stadium or Shanghai Railway Station (note that passengers must leave the station to make the transfer between the two lines and can only be completed if they are holding at Shanghai Transportation Card)