Mr. Raja Kumar on Instagram: "Over 2,400 years ago, ancient China created a mechanical device that could detect earthquakes without electronics. Using gravity, levers, and precision engineering, it could even show the direction of a distant quake. Modern seismology didn’t exist — but this machine still worked. In this video: • ancient Chinese engineering • early earthquake detection device • mechanical seismograph explained • technology ahead of its time 👉 Subscribe to Facts TV 91 for ancient i