For more than a century, Chicago has been a workshop to the world. The city nurtured thousands of companies that supplied a hungry market with industrial products. Successful firms that survived nearly 100 years are Mars Candy, Motorola Inc., Abbot Labs, Radio Flyer, Rand McNally, and others. Aged companies that sold off their brands or were bought-out entirely include Schwinn Bikes, Sears Stores, Pullman Rail Cars, Bell & Howell Cameras, and more...