Taquería El Califa de León, in Mexico City.GUSTAVO GRAF/ReutersA taco stand in Mexico City has been awarded a Michelin star.It is the first taco stand to win the award in Mexico.The taquería's simple but "exceptional" Gaonera taco has been key to its success.A small taco stand in Mexico City has been awarded a much coveted Michelin star as part of the guide's first Mexican edition.The 10-foot by 10-foot Taquería El Califa de León was founded more than 50 years ago in the Mexican capital's San Rafael neighborhood.And while the "bare bones" stand has "just enough room for a handful of diners to stand at the counter," it's distinguished itself as one of Mexico's best eateries — partly thanks to its "exceptional" Gaonera taco, the Michelin Guide says on its website."Thinly sliced beef filet is expertly cooked to order, seasoned with only salt and a squeeze of lime," the Guide says.