On Wednesday, May 15, 1940, brothers Richard and Maurice “Mac” McDonald opened the first McDonald’s restaurant in San Bernardino, California, as a barbecue restaurant. In 1948 they reorganized their business as a hamburger stand, using production-line principles. Businessman Ray Kroc joined the company as a franchise agent in 1955. He subsequently purchased the chain from the McDonald brothers and oversaw its worldwide growth. Above: the original McDonald’s hamburger restaurant.