National Microwave Oven Day is observed worldwide every December 6, celebrating the convenience and utility of microwave ovens in modern kitchens. The holiday recognizes the microwave oven's history, which began in the 1920s with the discovery that high-frequency radio waves could heat substances. Percy Spencer, an American physicist, accidentally discovered the cooking potential of microwaves while working with radar technology, leading to the first commercially available microwave oven produced by Raytheon in 1947. Over the years, microwave ovens have become a staple in households, with about 90% of U.S. homes owning one. People celebrate by cooking or reheating food in their microwaves, cleaning the appliance, or purchasing new models. Social media engagement is encouraged using hashtags like #NationalMicrowaveOvenDay and #MicrowaveOvenDay.