Restaurant chains are groups of related restaurants that share a common brand and menu. They operate multiple locations, often across different cities or countries, providing customers with a familiar dining experience. Popular examples include McDonald's, Starbucks, and Subway. These chains benefit from economies of scale, allowing them to offer consistent quality and pricing. Many restaurant chains use standardized recipes and training programs to ensure that food and service are uniform across all locations. This consistency helps build customer loyalty, as diners know what to expect when they visit any branch of the chain. Additionally, chains often engage in marketing campaigns to promote their brand and attract new customers.