There's a Documentary i watched recently, The.Phenomenon (2020). Check it out if you're bored. There was one incident that I find fairly convincing.
The incident had 62 eye witnesses, school children in Zimbabwe in 1994:
https://en.wikipedia.org/wiki/Ariel_School_UFO_incident
I don't believe 62 children could make up something like this, all their witness accounts matched up. They interviewed some of the students in the documentary, grown up of course, and they still claim it did happen.
I firmly believe we have had visitors, it's mathematically impossible that earth is the only planet with intelligent life.
The posters who said "why would they travel so far just to look around" with the technology they have travel to earth could be very easy for all we know. I think it's plausible that they would come here to explore and study without "eating or greeting" us. I wish they would greet us, I hope it happens in my lifetime, that would be amazing.