Central Axis
The central axis determines the symmetrical layout of traditional Chinese buildings. An important feature of traditional Chinese architectural and urban layout, it originated from the ancient Chinese understanding of the axis of the heavens and the earth. Most of the important groups of buildings in ancient China had a symmetrical layout along a central axis, with the main buildings constructed along the axis or on its two sides. The buildings follow a rigorous layout, with clearly-divided sections from the north to the south, and symmetrical distribu- tion on the eastern and western sides.
The architectural layout based on the central axis is cou- pled with the preference for being in the center and facing the south with the back of the building to the north. Because of such preferences, most ancient Chinese capitals were relatively square. The Central Axis of Beijing is the epitome of this architectural layout; it organizes the four layers of the city-the outer city, the inner city, the imperial city, and the imperial palaces, which form a unique urban architectural order. The imperial palaces, also known as the Forbidden City, occupy the very center of the city. The axis is 7.8 kilometers long, starting in the south of the city from the Yongding Gate, running across the Tian'anmen Rostrum, the Meridian Gate, the Forbidden City, and the Jingshan Hill, and ending with the Drum Tower and Bell Tower in the north. It is an important symbol of Beijing and the longest surviving urban central axis in the world.
The central axis is a prominent feature of the architectural layout of ancient Chinese capitals. The construction of the cap- ital was based on a central axis from the earliest Xia and Shang dynasties all the way to the Ming and Qing dynasties. After the founding of the People's Republic of China in 1949, the construction of Beijing continued to follow this symmetrical layout. The central axis embodies Chinese civilization's emphasis on the doctrine of the mean and the pursuit of harmony, and demonstrates the Chinese understanding of politics, culture, and living spaces.
中軸線
中軸線是中國傳統建筑物（群）中軸對稱布局的中心線，是中國傳統建筑格局與城市布局的重要特征，源于古代中國人對于天地軸線的理解。中國古代重要建筑大多呈中軸對稱格局，主要建筑按照一定的原則分布在中軸線及其兩側，南北層次分明，東西對稱分布，布局嚴謹。
中軸線的建筑格局與“居中”“居北”“面南”的觀念有機結合。基于這種理念，中國古代都城大多較為方正。北京中軸線是中軸線建筑格局的集大成者，有外城、內城、皇城、宮城四重城闕，故宮在最中心，形成了獨特的城市建筑秩序。北京中軸線南起永定門，經天安門、午門，穿過故宮的太和殿、中和殿、保和殿，越過景山，北至鐘鼓樓，全長7.8公里，是北京城的重要標志，也是世界上現存最長的城市中軸線。
中軸線是中國古代都城建筑格局的突出體現。從夏商時期的偃師、秦漢時期的長安城、漢魏時期的洛陽、隋唐時期的長安，到燕下都、金中都、元大都和明清北京城，再到1949年后的北京城建設，都是以一條軸線為中心對稱的格局。中軸線體現了中華文明以中為本、以和為貴的精神，展示了中國人通過規劃布局表達對政治理念、文化象征和生活空間的認識發展。
