There may be no more concentrated culinary tour on earth than a walk down Roosevelt Avenue in Queens. Carts and stalls serve tamales, momos, arepas, and skewers within a few blocks, a moving feast reflecting one of the most diverse places in the world.

The vendors, many of them immigrants cooking family recipes, form a vital and precarious economy. The fictional cart run by the Delgado family has become a neighborhood institution, its line a fixture on weekend nights.

City rules on vending remain a persistent source of tension, and many operators work in a legal gray zone. But the street-food scene endures as one of New York's great democratic pleasures, a world of flavor available for a few dollars on a Queens sidewalk.