You're more likely to catch a sub than a train at these Subway stations. Doctor's Associates owns the Subway chain of sandwich shops, the world's largest quick-service restaurant chain by number of locations, having surpassed burger giant McDonald's. It boasts about 41,500 locations in more than 100 countries. Virtually all Subway restaurants are franchised and offer such fare as hot and cold sub sandwiches, turkey wraps, and salads. The eateries are located in freestanding buildings, as well as in airports, convenience stores, sports facilities, and other locations.