Why did Luna collapse?

Can you elaborate on the reasons behind the collapse of Luna? Was it due to a lack of stability in its algorithmic mechanism, or was it caused by external market factors? How did the depegging of UST from the US dollar contribute to the downfall? Additionally, what role did the community sentiment and panic selling play in accelerating the decline? Lastly, what lessons can be learned from this incident to prevent similar collapses in the future?