Subway is the largest fast food franchise in the world, with over 37,000 locations across 100+ countries. It was founded in 1965 in Bridgeport, Connecticut by Fred DeLuca and Peter Buck. Subway focuses on providing customizable submarine sandwiches and allows customers to choose their sandwich toppings. While it has experienced success through its large global presence and emphasis on fresh ingredients, Subway also faces challenges like inconsistent quality across stores and changing customer preferences toward healthier, locally-sourced options.