The Beijing Central Axis (轴线) is the longest city axis in the world today. It was built in the 13th century and formed in the 16th century. It is 7.8 kilometers long. It runs through the old city of Beijing from Yongdingmen in the south to the Bell and Drum Tower in the north.
There are 15 sites along the axis, such as Temple of Heaven and Imperial Palace. Most of them are on the central axis, but the Temple of Heaven and the Altar of Agriculture, the Imperial Ancestral Temple and the Altar of the Land and Grain are not on the central axis. They are close to the east and west sides of the central axis.
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