Trivia

One of the three films that received an "F" CinemaScore from audiences upon their release in 2002, along with Feardotcom (2002) and Solaris (2002).

Director Jaume Balagueró attempted to recruit actress Natalie Portman to play the part of Regina, which eventually went to Anna Paquin.

The unedited R-rated cut (which was screened internationally) was eventually released on home video by Echo Bridge Entertainment, restoring 15 minutes of footage clocking in at 103 minutes, as opposed to the theatrical cut's 88 minute runtime. The Echo Bridge DVD and Blu-ray releases have since gone out of print.

Miramax/Dimension had paid $4 million for the rights to distribute the movie in North America and some other territories, but then shelved it for more than two years. The company gave the film a US theatrical release at Christmas 2004 after heavy editing to secure a PG-13 rating.

Fantastic Factory's fourth production after Faust: Love of the Damned (2000), Dagon (2001) and Arachnid (2001). It was followed by Beyond Re-Animator (2003), Romasanta (2004), Rottweiler (2004), La monja (2005) and Beneath Still Waters (2005). Fantastic Factory closed in 2005 after to fail in its attempt to create the first Spanish cinema company specialized in genre movies.

David Martí: special effects artist, as a man sleeping in the bus.