 Scenes at "St. John's Church" — the church featured in the episode — were shot in the actual St. Augustine Church in Vancouver, British Columbia. In order to secure permission for filming, the script was sent to the church's local Archdiocese for approval by a Monseigneur. Eventually, the script was approved and filming commenced. The production crew, however, scouted several other churches in case permission to film at St. Augustine fell through, although none of them had "the ornate physical presence" of the chosen church. Special stain-glass windows were created that featured an angel ascending into Heaven, to go along with the themes of the episode. Father McCue's book about the Nephilim was created by assistant art director Vivien Nishi with guidance from Spotnitz. Scenes at Father Gregory's church were filmed in an older boiler room at George Pearson Hospital. This location had previously been used in the earlier fifth season entry "Kitsunegari" as a cafeteria. The production crew initially worried that the high windows in the building would not allow the cameras enough time to film, as the light coming through would dramatically shift as the day wore on. A solution was devised in which some of the windows were lit up via artificial means.
