Harry Brearley was searching for a corrosion-resistant alloy for gun barrels when he noticed that a sample containing 12.8% chromium did not rust when exposed to air and moisture. He had accidentally invented 'rustless steel,' now known as stainless steel. The chromium reacts with oxygen to form a thin, invisible 'passive layer' of chromium oxide that prevents further corrosion. This invention revolutionized the food industry, surgery, and architecture, as it provided a material that was strong, easy to clean, and virtually indestructible. From kitchen cutlery and sinks to surgical scalpels and the skin of the Chrysler Building, stainless steel is a foundational material of the modern world, prized for its hygiene and longevity.