Door is an important structure connecting indoor and outdoor space, bearing people's yearning for safety, privacy and warmth. In human history, doors have always played an important role, not only as a physical barrier, but also as a carrier of culture, beliefs and symbols.

The door is a symbol of human civilization. It is not only an architectural structure, but also a cultural symbol. In ancient civilization, doors were often given symbolic meanings. For example, in the traditional culture of China, the door means "It's sad to close the door", which means that the past difficulties are shut out and new opportunities and hopes are waiting inside the door. In ancient Greece, doors were regarded as symbols of wisdom and knowledge, because they were usually located in front of schools and libraries. In religion, gates are often regarded as the entrance to the mysterious world, such as the gates of heaven and hell.

There are many kinds of doors, including wooden doors, iron doors, glass doors and security doors. Different kinds of doors have different functions and characteristics. Wooden doors are generally used in families, giving people a warm and comfortable feeling; Iron gates are usually used in shops and factories, with anti-theft and fire prevention functions; Glass doors are often used in shopping malls and office buildings to make indoor space brighter and more open. The security door has special locks and materials, which can provide higher security.

Doors also play an important role in architecture. It not only separates the inner and outer space, but also can be used to divide different functional areas, such as front door, back door, living room door, bedroom door and so on. In interior design, the design and color of doors are often used to increase the aesthetic feeling and layering of space. For example, choosing a warm door can make the space warmer, and choosing an unpopular door can make the space more modern and calm.

Besides its practical function, doors are often used to convey culture and art. Many cultures have myths and legends about doors, such as China's "Tianmen" and "Tunnel Gate", which are all related to legends and myths. In paintings and sculptures, doors are often used as themes, such as Van Gogh's Cemetery at the Church Gate and Rodin's The Thinker.

Generally speaking, the door is a symbol of human civilization. It is not only the architectural structure, but also the embodiment of culture, belief and art. It connects the inner world and the outer world of human beings and conveys people's yearning for safety, warmth and a better life. Whether at home, in shops or in religious places, doors bear people's dreams and hopes and are an indispensable part of human civilization.