Cast iron is a strong, heavy metal made mostly from iron mixed with carbon. Unlike steel, which bends before breaking, cast iron is hard and brittle: it can crack if dropped but resists wear incredibly well.

The name comes from how it's made. Workers heat iron until it melts into liquid, then pour (or cast) it into molds shaped like pans, pipes, or machine parts. When the metal cools and hardens, it takes the exact shape of the mold. This casting process has been used for thousands of years to make everything from cannons to cooking pots.

Cast iron cookware, especially skillets, remains popular because it heats evenly and lasts for generations. A well-seasoned cast iron pan develops a natural nonstick coating and can go from stovetop to oven without any trouble. Many families pass down their cast iron pans through generations: a pan your great-grandmother used might still cook perfect pancakes today.

Beyond the kitchen, cast iron appears in manhole covers, engine blocks, and old radiators. Its durability and heat resistance make it perfect for jobs requiring strength and the ability to withstand high temperatures. When something is described as having a cast iron stomach, it means they can eat anything without getting sick, borrowing the metal's reputation for toughness.