What if it was cloudy?
But this would be my biggest wish if aliens ever do make contact - that they have been recording everything on Earth with their huge telescopes for thousands of years, so we might get to see Julius Ceaser and his Roman legions conquering Gaul and stuff.
It might not even require telescopes on planets light years away either if the aliens/UAPs have always been here.
https://www.space.com/space-explorat...esearchers-say