Connecting the eastern shore of the Kunming Lake to the Nanhu Island in the west, the Seventeen-Arch Bridge is a major attraction of the Kunming Lake. With a length of 150 meters (164 yards) and a width of 8 meters (8.75 yards), it is the longest bridge in the Summer Palace, built during the reign of Emperor Qianlong (1711-1799). Highly inspired from other famous Chinese bridges such as the Lugou Bridge in Beijing and Baodai Bridge in Suzhou (Zhejiang Province), the Seventeen-Arch Bridge looks like a rainbow arching over the water. 544 distinctive white marble lions are carved on the column of the parapets with a bizarre beast on each end of the bridge.

An interesting legend connecting to the construction of this bridge can be noticed. Coming to the court to sell his "Longmen stone", a poor old man didn't receive any attention from the people who started to despise him because of his poor looking. Waiting for a buyer, the old man sat beside a tree but the rain forced him to shelter in some places. Kindly advised and sheltered by a man, the old man offered his Longmen Stone as a gift to his host to thank him, and returned home. Years after the beginning of the construction of the Seventeen-Arch Bridge, just one stone was missing but no one could find nor design the appropriate shape. Remembering about the old man, people started to look for him in the vicinity but just found the exact stone given years ago to the host. Fitting perfectly, the stone completed the construction of the bridge that could start to be used by the Emperor. Since then, the old man is believed to be the incarnation of Luban, ancestor of carpenters, who came to help people build the imperial bridge.