4. Shanhaiguan山海關 The pass of Shanhaiguan is a square, with a perimeter of around 4 kilometers long. The walls reach a height of 14 meters, and are 7 meters thick. In the middle of the pass stands a tall arrow tower. 山海關是一個廣場,一個周長約為 4公里長。城牆高達 14米,有7米厚。在中間矗立著一座高大的箭樓。 Old Dragon's Head 老龍頭 The place where the wall meets the sea. It is a popular tourist destination. 城牆伸入海中處,是一個熱門的旅遊景點。