in the center of mexico, this sprawling metropolis is the country's capital. [lively music] over centuries, it's held a magnetic appeal for immigrants, drawing them in from all over the world to make it their home, bringing a wealth of culinary influences with them. in the last 70 years, its population has exploded from 3 million to 22 million. and if chilangos were a food, they'd be a taco. they are the lifeblood here... the perfect fuel to eat on the go when powering through this crazy, busy city. ♪ ♪ hola! - hi, eva. nice to meet you! - gabriela rentería is a journalist who writes about tacos. i mean, talk about a dream job. you're never not happy eating a taco. i'll say that. - never. like, never. and you never get enough. [upbeat music]