If you ask people in the city of Mexicali, Mexico, about their most notable regional cuisine, they won't say street tacos or mole. They'll say Chinese food. There are as many as 200 Chinese restaurants in the city.
North of the border, in California's rural Imperial County, the population is mostly Latino, but Chinese restaurants are packed. There are dishes in this region you won't find anywhere else, and the history behind them goes back more than 130 years.