The title of the loudest vehicle on earth generally belongs to the Saturn V rocket, the massive vehicle used by NASA for the Apollo moon missions. At liftoff, the Saturn V generated a staggering sound level of approximately 204 decibels (dB). To put this in perspective, sounds above 85 dB can cause permanent hearing damage, and the decibel scale is logarithmic, meaning 204 dB is millions of times more intense than a jet engine at takeoff (approx. 140 dB). The sound was so powerful that it could melt concrete and was audible for miles. In the realm of modern atmospheric vehicles, the Republic XF-84H "Thunderscreech"—an experimental turboprop aircraft—is often cited as the loudest plane ever built. Its propeller tips moved at supersonic speeds even while idling, creating a continuous sonic boom that reportedly made ground crews physically ill and could be heard 25 miles away. In 2026, these extreme examples remain benchmarks for acoustic engineering and the sheer physical power of propulsion.