The Xi’ An city wall is the most complete city wall remaining in China. It stands 40 feet tall, 40-46 feet wide at the top and 50-60 feet thick at the bottom. It covers 8.5 miles in length with a deep moat surrounding it. Every 400 feet there is a rampart which extends out from the main wall. All together, there are 98 ramparts, which were built to defend against the enemy climbing up. Each rampart has a sentry building, in which the soldiers could protect the entire wall without exposing themselves to the enemy. Besides, the distance between every two ramparts is just within the range of an arrow shot from either side. On the outer side of the city wall, there are 5,948 crenellations, or battlements. On the inner side, parapets were built to protect the soldiers from falling off. The wall is now open for walking and bicycling.