Messages sent via pipes in Great Wall

During ancient times, an ingenious method was used to send messages along the Great Wall of China using a system of pipes. This early form of communication involved hollow pipes or tubes embedded within the structure of the Wall, allowing sound to travel through them over long distances. Guards and soldiers stationed along the Great Wall could shout messages into these pipes, effectively transmitting information and warnings quickly along the Wall’s extensive length. This method was part of a broader signaling system that included beacon towers and smoke signals, designed to provide rapid communication and coordination in response to invasions and other threats.