Our first stop on Day 2 in Nanjing was Zhonghua gate. This gate was the main gate to the city and is absolutely massive. In fact, it is actually several gates layered together, constructed to trap any enemy foolish enough to attack through this gate.
Hidden within the gate are many rooms which were used to store weapons and hide soldiers in the case of an attack. We liked hiding in these to cool down from the blistering heat outside. Inside was like a refridgerator.
The wall is built not with stone, but with clay bricks. Each brick has the insignia of the maker. This ensured the quality of each brick. If a brick was not holding up, they knew who to blame.
Here is a model of the Nanjing city wall. While some has been destroyed over the ages, quite a bit of it remains intact and you can see it as you walk around the city.
When you come up on top of the gate, you can walk along the top of the wall. The entrance fee you pay allows you to walk a few kilometers along the wall with various points where you can get off if you like. Because of the blistering heat we didn't walk very far and then we turned around and went back out through the Zhonghua Gate again. In cooler weather, this would be a very pleasant walk though.
Entrance fee at the Zhonghua Gate is 35 RMB and we felt it was well worth the price.