1921: The first White Castle restaurant opens with just four menu items – hamburgers, Coca-Cola, coffee and apple pie.
1924: White Castle becomes one of the first companies to provide health insurance for team members.
1927: Founder Billy Ingram invents the idea of restaurant “carry out” and unveils the tagline “Selling ‘em by the Sack.”
1934: White Castle moves its home office from Wichita, Kansas, to Columbus, Ohio.
1947: Cincinnati Castle operator Earl Howell introduces the idea of adding five holes to the patty, enhancing the flavor and helping it cook faster.
1961: White Castle becomes first fast-food chain to sell one billion burgers.
1962: Forty-one years after opening, White Castle adds its first new menu item, the cheeseburger.
1970: White Castle introduces “Hamburgers to Fly” program, shipping hamburgers via air express to those who live far from a White Castle restaurant.
1986: White Castle introduces breakfast sandwiches.
1987: White Castle makes frozen sliders available in grocery stores across the U.S.
1990: White Castle creates turkey stuffing recipe using 10 Original Sliders.
1991: White Castle accepts reservations for Valentine’s Day dinners.
1997: Gerard Hogan publishes “Selling ‘em by the Sack.”
2001: White Castle inducts first class of Cravers Hall of Famers.
2001: White Castle debuts Crave Case packaging containing 30 sliders.
2004: White Castle introduces the Crave Crate containing 100 sliders.
2014: White Castle offers breakfast 24 hours a day.
2015: White Castle introduces Veggie Sliders.
2018: Impossible Slider debuts at White Castle, the first fast food chain to offer the burger made from plants.Source: White Castle