The Invisibility Task Force was an office of the Ministry of Magic that was presumably a part of the Department of Magical Accidents and Catastrophes. Its job was to keep magical creatures and places in the wizarding world out of sight of Muggles.
It is likely that it was this office that cast the spell which made Muggles suddenly remember urgent appointments when they get too near the site of the Quidditch World Cup Stadium.
It is also likely that it was this office that cast the spell which made Muggles see an old ruin of a castle when they were really looking at Hogwarts School of Witchcraft and Wizardry. It is likely that the office also made Hogwarts Castle Unplottable.
Azkaban, the wizarding prison, is also Unplottable, and has certain concealment charms placed on it, hiding it from Muggle view. It is presumed that it was this office that made it so.
- Daily Prophet Newsletters (First appearance)
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