The Hidden City () is a 2018 documentary film directed by Víctor Moreno. The film explores the underground structures and systems beneath Madrid, Spain, including sewers,  train tunnels, subterranean rivers, and man-made caverns . An international co-production between Spain, Germany and France, The Hidden City premiered at the Seville European Film Festival in November 2018. 
The Hidden City () is a 2018 documentary film directed by Víctor Moreno. The film explores the underground infrastructure beneath Madrid, Spain, including sewers, pipes, walls, train tunnels, and man-made corridors, featuring maintenance workers, commuters, and animals . An international co-production between Spain, Germany and France, The Hidden City premiered at the Seville European Film Festival in November 2018. Synopsis The Hidden City is comprised primarily of footage of subterranean structures and systems beneath Madrid, Spain, both filmed by director of photography José Ángel Alayón and by surveillance cameras. Elements presented include train tracks and tunnels; sewer pipes and dripping brick walls; underground workers; animals—such as an owl, cockroaches, rats, and feral cats; human commuters travelling by metro; and microscopic views of microorganisms in sewage water. The film features no dialogue aside from occasional commands received by portable communicators.
R
structures and systems
infrastructure
A
pipes, walls,
D
subterranean rivers,
R
caverns
corridors, featuring maintenance workers, commuters, and animals
A
Synopsis The Hidden City is comprised primarily of footage of subterranean structures and systems beneath Madrid, Spain, both filmed by director of photography José Ángel Alayón and by surveillance cameras. Elements presented include train tracks and tunnels; sewer pipes and dripping brick walls; underground workers; animals—such as an owl, cockroaches, rats, and feral cats; human commuters travelling by metro; and microscopic views of microorganisms in sewage water. The film features no dialogue aside from occasional commands received by portable communicators.