McDonald's started in 1940 and became the world's leading hamburger chain after being franchised by Ray Kroc in 1955. It expanded globally through reinforced quality, service, cleanliness and value. Key to its success was targeting children through Ronald McDonald and maintaining consistency. However, international expansion led to decreased quality. More recently, it faces risks from health-conscious consumers avoiding high-fat products. McDonald's responded by adding healthier options and refurbishing restaurants.