Xian is a well-known tourist city in China, you have to visit Old City Wall of Xian while travelling to China.
This is the most complete city wall in China still in existence, the Xian city wall was built in Ming dynasty(1368--1644AD), running approximately 14 km in length and featuring impressive guard towers and gates. The wall is fully linked now with access provided at the major gates, making it a great way to get a feel about the old Xian.
As there are four main gates including East, West, North and South Gate. It is very convenient to walk from Muslim Quater to South Gate along the South Street, then you can wander around the historical city wall. Afterwards you are advised to visit Beilin Museum which is near the south gate after you go across the market.
You can take a ride on the wall, and the bikes can be rented on each city gate. There is also electric cart to run around the wall for about 100 minutes.