A McDonald's in Las Vegas. Image source: McDonald's. The first McDonald's location was in Fresno, California, and franchised by founder Ray Kroc. Today more than 30,300 McDonald's are operated by franchisees. 

When you have as long and as storied a history as does McDonald's (MCD -0.75%), you're bound to revolutionize how your industry operates. For example, although the Chicken McNugget was invented in the 1970s, scalable production wasn't available until 1983, when the company was able to replace the slow-selling Onion Nugget, and boneless chicken bites suddenly became a huge thing.

And while it may be known that its famous Golden Arches were not representative of the letter "M" in the McDonald's name until five years after they debuted, but rather signified the restaurant's architecture, there are dozens if not hundreds of interesting facts about this iconic and ubiquitous fast-food chain.

Below are 13 more fascinating things you probably didn't know about the hamburger king.

  1. The first food McDonald's served was hot dogs, not hamburgers.
  2. The chain operates some 36,000 restaurants -- many more than Burger King (15,100), Wendy's (6,500), and Sonic (3,500) combined.
  3. According to its operations and training manual, McDonald's sells "more than 75 hamburgers per second, of every minute, of every hour, of every day of the year."
  4. Ronald McDonald was first introduced in 1966, and the clown character is by some reckonings the second-most recognizable character in the world behind Santa Claus, with one survey finding that 96% of all U.S. schoolchildren knew him.
  5. The Big Mac was first introduced in Pittsburgh in 1968.
  6. There are four Chicken McNugget shapes: the Boot, the Ball, the Bow Tie and the Bell.
  7. There are 2,400 quality checks involved in a single day's beef-patty production at the company's beef supplier, Cargill.
  8. Keystone Foods (which also helped create the Chicken McNugget) was created as a result of demand from McDonald's for its Individual Quick Freeze process, which kept beef patties fresh-tasting. The process is used by burger makers worldwide today.
  9. Cargill takes only about 21 days on average to process its beef and deliver it to a McDonald's restaurant, meaning a typical hamburger you eat at the restaurant was likely a cow chewing its cud just three weeks prior.
  10. McDonald's famous french fries are "peeled" via high-pressure steam at supplier McCain's facility, then shot through a slicer at about 40 mph to achieve the uniform shape for which they're known.
  11. In the U.S., McDonald's purchases more than 13 million cage-free eggs each year, or about 10% of the 130 million eggs the chain uses annually. It promises to be 100% cage-free by 2025.
  12. It's estimated McDonald's has served well over 300 billion hamburgers since its founding, but the company officially stopped keeping count somewhere around 1994, which is why the restaurant signs say either "Over 99 Billion Served" or "Billions and Billions Served."  
  13. McDonald's sold its 100 millionth burger in 1958 and surpassed 400 million two years later. It hit 700 million burgers by 1962, and the billionth burger was served in 1963 on the Art Linkletter TV show.  By 1983, McDonald's had sold 45 billion hamburgers, and then it grew by 5 billion burgers a year through 1993, when the 100 billionth burger never seemed to materialize.

A multiyear slide in sales may have stalled reaching the next milestone, whatever that happens to be. Yet McDonald's seems to have gotten itself back on track with three straight quarters of rising same-store sales. Investors are looking for four in a row when the company next reports earnings.