The Devil's Backbone

• Filmed on location in the Madrid region during 2000, including the Colegio de San Fernando and sites around Talamanca del Jarama, plus Cubillo de Uceda in Guadalajara for the orphanage exteriors.
• Santi's ghost was played on set by child actor Junio Valverde in practical makeup and prosthetics (his cracked, porcelain-like temple wound), with digital compositing work handled by Barcelona's DDT Studios to finish the effect.
• Del Toro has described the courtyard bomb as 'Chekhov's bomb, except it doesn't go off' -- a deliberate inversion of Chekhov's gun, since everything else in the story detonates except the literal bomb.
• Co-produced by Agustin and Pedro Almodovar's company El Deseo alongside Mexico's Tequila Gang; the Almodovar brothers gave del Toro full creative freedom to make the film in Spanish after his rough Hollywood experience on Mimic.
• The film underperformed at the U.S. box office, losing ground to the English-language ghost story The Others that same year, but earned strong critical notices (Roger Ebert gave it three stars) that helped secure del Toro the creative latitude he used five years later on Pan's Labyrinth.
• Marisa Paredes, who plays orphanage administrator Carmen, was already a major figure in Spanish cinema as one of Pedro Almodovar's recurring leading actresses (All About My Mother among others).

Santi isn't haunting the orphanage out of vengeance toward Carlos but toward Jacinto. His warnings to Carlos function as a dead child trying to prevent another child from becoming his replacement victim, making the ghost a protector figure twisted by his own trauma.

The gold isn't just Republican funds but functions as a literal curse object, corrupting everyone who desires it. Carmen keeps it and dies for it. Jacinto kills for it and ends up dragged down and drowned in the cistern under its weight. The film positions revolutionary ideals as something that inevitably devours its own children once it becomes capital.

Carlos is already dying or dead by the film's final scenes, and his narration throughout has been Santi's voice passing to the next ghost. The film's circular structure, opening and closing with the same narration about ghosts being 'a terrible tragedy,' suggests Carlos has joined Santi's loop rather than escaping it.

Spain, 1939. The Republic is bleeding out. Twelve-year-old Carlos gets dumped at a crumbling orphanage run by Republicans hiding gold meant for the anti-fascist cause. An unexploded aerial bomb sits nose-down in the courtyard, ticking with dread. A drowned boy named Santi drifts through the halls whispering warnings. The groundskeeper Jacinto, a former orphanage ward turned predator, wants that gold and doesn't care who he burns alive to get it. Del Toro's first proper ghost story is less about things that go bump than about the rot that spreads when adults fail the children in their care.