According to director David Moreau star Olivia Bonamy suffered from claustrophobia and much of her performance as she crawled through the narrow tunnels was the result of her genuine fear of the tight spaces.
The house used in the film was an actual sprawling old estate in Bucharest, Romania. The house was so large that the production was unable to furnish all the rooms for shooting, but it was also large enough that the entire production worked out of the location.
Shot in 30 days.
Gave inspiration for the movie The Strangers (2008)
Piano notes played periodically throughout soundtrack was used in Space: Above and Beyond: Season 1, Episode 12 Who Monitors the Birds?(7 Jan. 1996)