Ok, so a super-duper covert group that exists within multiple world government agencies, especially the carefully vetted and heavily monitored security forces and investigative bureaus, somehow figured out that the location in Vienna was a major hive of vampire activity. This group then somehow arranged for a U.S. missile strike targeting the chantry, blamed the destruction on terrorist activity, and got away with it.
All this time, not one of the many mystical protections so much as flickered, not one of the elders so much as got a nudge from their in-clan Auspex, and not one of the many mortal and ghoul servitors across the city got even so much as a whiff of activity. The governments from which the manpower and supplies were stolen also didn't notice anything, investigate, or apparently even care.
Yup, it was truly magical.