In this article, the author describes how Cornwall was once the world's leading producer of tin. Cornwall's industrial past is now a World Heritage Site alongside the Grand Canyon or the Great Wall of China. A hint is in the Cornish flag, a simple white cross against a black background, also known as Saint Piran's flag. At Geevor Tin Mine, one of the last Cornish tin mines to close, Saint Piran's flag is flying and the site is being preserved as a heritage site telling the story of hard-rock tin mining. The author states that tin mining can be experienced by school groups through guided underground tours, an interactive museum, and the many evocative mine buildings still in place. (Contains 6 figures.)