Building Colors
The predominant color of the Great Wall is gray, resulting from the primary building materials of brick, stone, and tamped earth, which, over time, weather and erode to form a gray surface. Local climate and environmental factors can also influence the color, causing some sections to appear yellow or red. The shape of the Great Wall varies according to the terrain and defense needs; typically, the walls have a serrated profile with enemy towers, beacon towers, and passes integrated into the defense system.
Architectural Features
The Great Wall is vast, recognized as the longest and largest ancient defense project in the world, stretching over a wide area in northern and central China, totaling thousands of miles. Its defense system is comprehensive, composed of walls, watchtowers, passes, fortresses, camps, and beacon towers, forming a complete military engineering system. Its layout adheres to the principle of “using terrain to create obstacles,” utilizing geographical advantages and local materials to maximize defense and minimize resource expenditure.
The design of the walls is intricate, constructed on high mountains or in crucial lowland areas, with taller and sturdier structures in plains and narrow ones in mountainous regions. The tops of the walls feature inner walls and outer parapets, equipped with lookout points, shooting holes, and catapult openings. During the Ming Dynasty, enemy towers were built atop the walls to enhance defense capabilities. Key passes are strategically placed in favorable defensive terrains, like the renowned Shanhaiguan, Huangyaguan, and Juyongguan, with larger passes often accompanied by smaller ones, collectively forming a defensive system.
Beacon towers play a critical role in military communication, signaling troop movements through smoke by day and fire by night, later supplemented with cannon fire for added alertness. The layout of beacon towers is strategic, often placed on high mountains or within complex terrains, ensuring they can visually communicate with each other. Additionally, they provided safety, accommodation, and provisions for travelers and messengers.
