What role did the observation port, shooting port and city platform of the Great Wall play in ancient times?

The beacon tower is one of the most important components of the Wan Li Great Wall defense project. Its function is to serve as a facility for transmitting military information.

Lookout: Look at the military situation.

Pile: Cover yourself and attack the enemy.

Pile-to protect the body from arrows and bullets;

Lookout-used to observe the enemy's situation, terrain, surrounding environment and temporary dynamics;

Shooting port-used for archery, rolling stones, oil rolling, boiling water, shooting and other attacks;

Urban platform-command operations, patrol, mobilize troops, organize temporary meetings and use facilities!