Lesson
Black to move. Main line: 23... Qg3 24. hxg3 Ne2#
The queen lands on g3 where White can apparently capture it three ways. After 24.hxg3, 24...Ne2# works because the knight covers g1 and f4 while the rook on h3 controls the h-file. The captured queen has opened the exact lines Black needs.
The alternatives are no better. 24.fxg3 Ne2+ drives the king to h1 and 25...Rxf1 is mate; 24.Qxg3 Ne2+ followed by ...Nxg3 wins the queen with check. A sound sacrifice must survive the defender’s choices, and this one does.
The story that spectators showered the board with gold coins is famous but historically disputed. The chess is not: the published game score records 23...Qg3, and the legal continuations explain why Levitsky resigned rather than choose a capture.
If the f-pawn takes: 24. fxg3 Ne2+ 25. Kh1 Rxf1#
If the queen takes: 24. Qxg3 Ne2+ 25. Kh1 Nxg3+