As the world's largest city wall, the Xi'an city wall has been restored and is wide enough to easily ride 5 bikes across. The landscaped park around the base of the exterior walls and moat also makes for a pleasant stroll and gives a different perspective on the battlements and towers. There is a small museum inside the city walls at Hanguang Gate, about halfway between the southwest corner and the South Gate, accessible from the top of the city wall itself. Look for a staircase down inside a covered structure. Inside are the unrestored remains of a gatehouse and a calligraphy collection. The wall is lit up at night and makes for a pleasant stroll. The present city wall was built in the Ming dynasty on the foundation of the Chang'an Imperial city wall of Tang dynasty.