Who caused the downfall of Atlantis, was it a war involving extraterrestrials, and if so, which ones?

This was a war among the extraterrestrials and was specifically involving the Arcturians and the Reptilians. The Anunnaki, as always, were above the fray but the relative newcomers were jockeying for position and wanting to demonstrate their capabilities, and this was highly destructive for both and led to the near destruction of humanity yet again. This was the event leading to the fall of Atlantis approximately 26,000 years ago.