How did humans send warnings?

Join Mira and Finn on History's Not Boring by Kidopoly as we race against the clock to answer a life-saving question: before text messages and electricity, how did humans warn each other of danger? Imagine seeing enemies approaching and having to send a warning as fast as possible! Thousands of years ago, ancient civilizations lit massive signal fires on hilltops. Did you know the Great Wall of China had special beacon towers that could pass a warning message 700 miles in a single day?! Wow! We'll travel back in time to hear medieval village church bells ringing out in panic, and meet Claude Chappe, a French engineer who built giant moving wooden arms to wave messages across the country! Discover the invention of roaring ship sirens and learn how loud air raid sirens protected London during the Blitz. Finally, we'll blast into the present day to explore high-tech ocean tsunami buoys and earthquake alarms that give people a precious 30 seconds to get to safety! Get ready for a loud, exciting, and action-packed adventure through time!