White Castle opened its doors in 1921, and the franchise set out to make a better name for the hamburger in a time when the ground meat patty had a bad name in popular culture. Ahead of its time, White Castle also allowed people to see their food being made, a first at the time. Franchising was introduced the same year when A&W Root Beer franchised its popular syrup.
Combining these factors with Howard Johnson franchising its first restaurant in the 1930s, the stage was set for the takeoff of the industry. McDonald's opened its doors in 1948, instilling the first assembly-line-style restaurant, and from there, the fast food industry grew steadily for decades.
Burger King and Taco Bell opened their doors in the 1950s, and Wendy's followed in 1969. Drive-through windows took off at fast food chains with the advent of speaker systems in the 1950s. By 2005, the fast food industry had sales totalling over $163.5 billion worldwide. McDonald's, as of 2014, has over 30,000 franchised restaurants in 120 countries.
With its success, the fast food industry has come under much scrutiny for selling unhealthy foods, marketing extensively and aggressively to children, and undermining local cultures and values in different parts of the world.