In the Netherlands we have our annual remembrance moment on May 4th, at 20.00.
By NOTAM, the whole FIR below some sort of limit (I think FL65) is effectively closed from 19.58 to 20.10 or so, with all departures and arrivals timed so that they are either on the ground, or above that level during that period.
Furthermore, around the major remembrance sites there are RA(T)s in place for a much longer duration.