Most tourists enter the Summer Palace from the East Gate, while the North Gate is less crowded and closest to the Beigongmen Station of Metro Line 4. Entering from the North Gate is Suzhou Street, which is a shopping street based on Suzhou Shantang Street. Tickets must be purchased separately. Entering the North Gate is the back mountain of the Summer Palace. The attractions of the back mountain are Xumi Lingjing and the Four Continents, which are a group of mixed Han-Tibetan Buddhist buildings. In 1755, when suppressing the Junggar Rebellion, Qianlong received support from the upper echelons of the four tribes of the Mongolian Walut, and for this reason, he specially built the Four Continents in the back mountain in imitation of the Samye Monastery in Shannan, Tibet. The Four Continents of the Summer Palace and the Four Continents of the Puning Temple in the Eight Outer Temples of the Chengde Mountain Resort use the same drawings and the same construction team. In 1860, the British and French allied forces entered the Summer Palace and burned down the Xumi Spiritual Realm. The current structure was rebuilt in 1980. From 2010 to 2012, it underwent large-scale repairs to restore the four major continents. Above the four major continents is the Sea of Wisdom, which is the tallest building in the Summer Palace and was built during the Qianlong period. The Sea of Wisdom is a stone building. The hall enshrines countless Buddha statues. The outer layer is decorated with glazed tiles and carved with thousands of glazed Buddha statues. When the Eight-Power Allied Forces invaded, the Buddha statues were severely damaged, but now they have been repaired. Climbing up the Sea of Wisdom and looking down at Kunming Lake, one's heart is surging with emotion. History has passed here, and the stories that happened here are unforgettable.