Order a taco in East Los Angeles, California. It will come in a corn tortilla with carne asada (steak). In Dallas, Texas, chow down on a taco made with pit-grilled pork. Grab a taco with collard greens and albondigas (Mexican meatballs) in Memphis, Tennessee. In each place, you’re tasting a chapter of a story . . . the story of the Amazing Transforming Taco.

“No one owns the taco,” says José R. Ralat. He just wrote a book called American Tacos: A History and Guide. “It’s a living food, and I wanted to see how it is changing as we change.”

What makes a taco a taco? You know the basic idea. Yummy ingredients get stuffed into a hard tortilla shell or rolled up inside a soft one. But people around the United States are giving this old food a new life. Some tacos show Asian or Jewish ways of cooking. Others keep that classic Mexican taco style.

The taco has been changing for a long time. The United States and Mexico went to war in 1846. After winning the war, the United States took nearly a third of Mexico’s northern territory. Suddenly, some Mexicans became Mexican Americans. The taco north of the line was now on its own. People filled it with whatever was available. Mexicans in Texas had to use yellow cheese. People in New Mexico used red and green chile peppers. And taco flavors continually changed in California, where new people groups moved in and out all the time. Today you can even find Indian-style tacos made with curry and Korean tacos made with bigeye tuna sashimi.

Many say their taco recipe is “the real thing.” Who makes the most authentic Mexican taco? We may never know. But we can watch the taco to see how people are moving. People—and the taco—never stand still!