On Alexander the Great's Torching of Persepolis In 330 BC Being Revenge for Xerxes the Great's Razing of Athens In 480 BC

Alexander allegedly stated as much (this according to famed historians such as Plutarch, Quintus Rufus, et. al) but being that there was also an enormous amount of alcohol involved and an almost instantaneous regret by Alexander (after the booze wore off, I guess), I'm thinking that this was more of a major-league fuck-up than anything (plus he was probably pissed off at Darius for dragging the inevitable out and was looking for a huge exclamation point and boy did he ever get one).