While modern lightbulbs frequently burn out after a few hundred or thousand hours, one remarkable bulb in Livermore, California, has been continuously illuminated for 125 years. Known as the Centennial Light Bulb, it holds the Guinness World Record as the longest-lasting lightbulb in history and is celebrating its 125th anniversary on Saturday, September 19. Handcrafted by the Shelby Electric Company and designed by engineer Adolph Chaillet, the bulb was originally installed in a Livermore fire station in 1901 to provide overnight illumination for firefighters.
The secret behind its extraordinary longevity lies in its unique engineering. Unlike modern tungsten-filament bulbs, this carbon-filament bulb features a filament eight times thicker, operates at a very low wattage—glowing softly at around 4 watts today—and is sealed within a near-perfect vacuum that prevents the filament from overheating and burning out. While the bulb has occasionally gone dark over the decades, these rare interruptions were strictly due to power outages or relocation, rather than any internal failure. Today, this historical marvel continues to fascinate scientists, engineers, and tourists alike, drawing thousands of visitors to the fire station annually while being monitored 24/7 via a live webcam.
