What is the only tomb in the world where two emperors are buried together?

It is the tomb of Emperor Gaozong and Empress Wu Zetian of the Tang Dynasty, located in Ganling, north of Weihe River in Shaanxi Province, west of China. It is the only tomb where two emperors were buried together in the feudal history of China for more than 2,000 years. Emperor Li Zhi of the Tang Dynasty and Emperor Wu Zetian of the Zhou Dynasty were buried together in the tomb, representing the emperor and husband and wife respectively. Located in Liangshan Prefecture, 6 kilometers north of Ganxian County and 85 kilometers away from Xi City. Wu Zetian is the only female emperor in the history of China. Her life is full of legends. After her death, a huge stone tablet was erected in front of the mausoleum, but there were no words on it, which was called "the tablet without words". At present, Ganling is applying for World Cultural Heritage. The Tang Dynasty is the second climax of China mausoleum construction after Qin and Han Dynasties. ***2 1 emperors in the Tang dynasty, including Wu Zetian, except Wu Shi and Gao Zong, the last two emperors were buried in Yulu, and the rest were all on the north bank of Weishui in Shaanxi, which was called "Eighteen Mausoleums in Guanzhong" in history. Most of the tombs in the Tang Dynasty are "based on mountains", that is, using natural isolated mountains to cut through stones to form graves, which is more magnificent than artificial soil sealing. For example, the Ganling, where Emperor Gaozong and Wu Zetian were buried together, takes the main peak of Liangshan as the Lingshan, which is about 70 meters higher than the Shinto in front of the mausoleum and much more majestic than the "Fangshang" which was only about 20 or 30 meters high in the Qin and Han Dynasties. The tombs are set in the hilly Beishan Mountains, with the vast Guanzhong Plain in the south, facing the mountains and Taibai in the south. The Weihe River is far ahead, where water mirrors haunt. Near it, there are shallow and deep. Looking around, the plain is separated by millet and seedlings, and the vast plain is silent, which highlights the peak of Lingshan. The Tang Mausoleum inherited and further developed the tradition of the Han Mausoleum, and formed a grand composition representing the residence of emperors: a square wall was built around the Mausoleum, called the inner city, with doors in the middle of all sides and gatehouses and watchtowers at the four corners; There is a sacrificial hall in Zhuquemen, the south gate, where a big sacrificial ceremony is held. Outside the Suzaku Gate, there is a Shinto that is three or four kilometers long. At the southernmost tip, it starts with a pair of earthen caves, followed by a gate. From there, the second pair of soil que and the second door are about a few hundred meters to one kilometer north of Suzaku Gate, and then it leads to the third pair of soil que in front of Suzaku Gate. First, there are many tombs in the vast area between the two gates, among which the number of tombs in Zhaoling of Emperor Taizong is the largest, reaching 167. The whole mausoleum is very large in area. Zhaoling and Xuanzong Mausoleums cover 60 kilometers a week, surpassing Guo Cheng in Chang 'an. Ganling is next, 40 kilometers per week, equivalent to Chang 'an. The following tombs range from 10 km to more than 30 km, of which Ganling is the best preserved. The stone carvings in the Tang tombs are also wonderful: the stone carvings are arranged on both sides of Shinto. Take Ganling as an example. From the second gate to the north, from south to north, a pair of Chinese watches, a pair of winged horses, a pair of embossed ostriches, five pairs of horses and ten pairs of stone men are arranged. In addition, there are wordless tablets and sacred tablets between the stone man and Sanque, and there are sixty-one stone statues of Wang Bin between the Shishi in front of Sanque and the Suzaku in the north. Just like the south gate, there are a pair of stone lions and a pair of earth que outside the inner gate. There are three pairs of horses outside the Tuque in the North Gate, numbered as "Six Dragons", which means that they are stables in the Emperor's Palace. Pine, cypress, Sophora japonica and poplar are widely planted in the mausoleum area to set off stone carvings. These stone carvings undoubtedly enriched the content of the mausoleum, expanded the control space of the mausoleum, and compared the height of the mausoleum, which played a great role in rendering the majestic and lofty atmosphere.