潜水观长城

Wall in this area spans approximately 50 kilometers and features 21 beacon towers.
In 1975, the Chinese government constructed the Panjiakou Reservoir, the largest water conservancy project in northern China, here. After the reservoir was filled, the water level exceeded the height of the Great Wall, submerging the Xifengkou and Panjiakou castles. From then on, this section of the Great Wall, which had endured five centuries of vicissitudes, vanished beneath the water.
喜峰口、潘家口长城是中国明代长城的两个重要关隘，是当时中原通往北疆和东北边陲的咽喉要道，这一带的长城长约50公里，共有墩台21座。
1975年，中国政府在这里修建华北地区最大的水利枢纽工程-一潘家口水库，蓄水后水位超过了长城高度，喜峰口、潘家口城堡淹没于水中，从此这段历经五百年沧桑的长城便隐身水下。