• “Which Way Home”

“Huge cities — they show them in movies and on TV, and now I want to see it live.”

So says a teenage boy riding on the roof of “The Beast,” a train rumbling through Mexico carrying child migrants from across Latin America into the U.S.

Rebecca Cammisa and her small film crew rode “The Beast” and interviewed its hopeful stowaways for her HBO documentary Which Way Home, screening Friday Dec. 11 at Chicago Filmmakers.