Tacos have deep roots in Mexican cooking, but the basic idea reaches back long before the modern taco had a name. People in Mesoamerica were eating food with corn tortillas centuries before Spanish colonization, using them as a practical way to hold meat, beans, chiles, and other ingredients.
Over time, tacos developed into countless regional styles across Mexico. Geography played a large role. Coastal communities made use of fish and seafood, while cattle ranching influenced the cooking of northern Mexico. In cities, street vendors helped turn tacos into inexpensive meals that could be prepared quickly and eaten almost anywhere.
Immigration also shaped the taco. Lebanese immigrants who arrived in Mexico in the late 19th and early 20th centuries brought traditions of spit-roasted meat, techniques that eventually helped inspire tacos al pastor.
Tacos continued to evolve after crossing into the United States. Mexican American cooks adapted recipes to local ingredients and tastes, while restaurants helped introduce tacos to a much larger audience.
That history helps explain why tacos are difficult to define with a single recipe. The tortilla provides the foundation, but everything else can change. National Taco Day celebrates a food that has remained remarkably simple while becoming almost endlessly adaptable.