
Wonders in the sky and men fainting with fear and with foreboding of what is coming on the world.
Examples that could resolve this market as "YES":
- Big impact on the Moon that is shocking to naked eye observers 
- An exceptionally bright comet visible during the day, at minimum matching the Great Comet of 1744 (magnitude −7) with striking tail 
- Supernova no dimmer than SN 1006 (-7.5 mag) 
- Satellite constellation similar to Starlink trains, but order of magnitude more striking 
- A big space station visible to the naked eye with angular diameter larger than the moon 
- Perhaps some extreme northern lights (if even physically possible) visible on all latitudes, turning night into day, etc. 
- etc. 
Should be seen from multiple continents; a bright meteor will not normally count.
@mariopasquato as long as they fit the criterion for auroras, multiple continents, etc. I will be super strict with auroras and bolides since I don’t want anything remotely ordinary to count.
@mariopasquato The explosion itself in insufficient because it is too localised geographically. However in combination with, per Wikipedia, "auroras [...] observed in the detonation area, as well as in the southern conjugate region on the other side of the equator from the detonation" I think it would count if the auroras in the conjugated region were noticeable to unsuspecting observers.
Two such explosions in different places within a short time interval would count by themselves.
How about a projected hologram advertisement on the moon? https://www.linkedin.com/pulse/marketing-moon-turning-night-sky-billboard-amol-naresh?utm_source=share&utm_medium=member_ios&utm_campaign=share_via
@BTE this may be far too physically challenging to be worth the investment
@BTE Borderline case .. only if it was seen from multiple continents as an extraordinarily bright bolide (definitely brighter than the Chelyabinsk 2013 meteor - I will not resolve for a regular bolide) before impacting .. which I don't think was the case.
I see Tunguska was accompanied by ice/dust clouds visible over Europe, so depends on whether those were striking to a naked eye observer. Combination of the bolide, impact, and the clouds could just have been enough to cross the threshold.
A necessary criterion is that it has to be a striking sight to unsuspecting observers on multiple continents.