O-O-O to Mate

1. d4 f5 2. e4 fxe4 3. Nc3 Nf6 4. Bg5 e6 5. Nxe4 Be7 6. Bxf6 Bxf6 7.
Nf3 O-O 8. Bd3 b6 9. Ne5 Bb7 10.  Qh5 Qe7 11. Qxh7+ Kxh7 12. Nxf6+ Kh6
13. Neg4+ Kg5 14. h4+ Kf4 15. g3+ Kf3 16. Be2+ Kg2 17. Rh2+ Kg1

*drum roll*

18. Kd2 mate

Now, as you know, 18. O-O-O (mate) is given by some sources, which was possible, but I believe was not Lasker's choice. I recall he commented after the game that the King move was more aesthetic, in his view.

Dave Regis http://www.ex.ac.uk/~dregis/DR/chess.html