Paulsen–Morphy, from the First American Chess Congress, New York 1857 — one of the most famous games ever played, crowned by Morphy's astonishing queen sacrifice 17…Q×f3. Emanuel Lasker presents and annotates it in his lecture series Common Sense in Chess (1896); his public-domain notes are reproduced below.

1. 7.Nxc6 This capture only develops Black. It would have been quite as good to retire with the Kt to B 3 and to follow this up, if (7) ..., Kt x P by (8) P - Q 4.
2. 9.Be2 The Black Pawns by thus advancing do not of course gain in defensive strength, but Black is so far ahead in development that White will never be able to take advantage of that weakness.
3. 11.Bf3 If here (11) P - Q B 3, which looks at first sight stronger, then Black will assail the castled King, which for the present is the only support of the K R and K Kt Pawn. The game might proceed (11) ..., Q - R 5; (12) P - K Kt 3, Q - R 6; (13) B - B 3, R - R 5; (14) P x R, B - Q 3; or (12) P - Q 4, B - Q 3; (13) P - K Kt 3, Q - R 6; (14) P - K B 4, B - Q 2; (15) B - B 3, R - K 2; when Black will double his Rooks on the K file and obtain a sound position with many attacking possibilities.
4. 12.c3 A somewhat elaborate process for so simple an object. First, P - Q 3 was the proper play.
5. 12…Qd3 This is one of the rare cases, in which a heavy piece like the Queen can with success be used for the purpose of obstruction. The Queen cannot be attacked in her present situation by any hostile man but exerts a considerable amount of pressure, preventing, for instance, such moves as Q - B 2 or B - K 2.
6. 16.Ra2 This move may serve as a preparation for Q - B 2. White evidently is beginning to feel the restraint which he suffers through the blockade of his Q P by the adverse Queen. His plan, however, is frustrated by Black, whose attack has already become ripe for a decisive blow. If (16) Q - R 6 instead, Black's best reply seems to be (16) ..., Q - B 4; (17) P - Q 4, Q R - K; (18) B - K 3, P - Q B 4; (19) Kt P x P, B x P; (20) Q - R 5 ?, R - K Kt 3, with a winning advantage, for if (21) K - R, Q x B, (22) P x Q, B - B 3, leaves White helpless; therefore White's best would be (20) Q - K 2, B - Kt 3; (21) B - Kt 4, R x B; (22) B x Q, R x Q; (23) B x B with an even ending.
7. 16…Rae8 The strongest move for development and simultaneously for attack. Black threatens now Q x R ch.
8. 17…Qxf3 An effective, surprising, and beautiful coup.
9. 19…Bh3 Black threatens B - Kt 7 ch., followed by B x P mate. R - K Kt is no safeguard, as after the exchange of the Rooks the Q R will checkmate him. Nor would (20) Q - Q 3 mend matters, as Black will answer with P - K B 4, and if then (21) Q - B 4 ch., by K - B.
10. 22…Bg2+ He might have decided the issue by R - Kt 7, with the double threat R x P ch., etc., and R x R P.
11. 25.Qf1 His only resource.
12. 26…Re2 Again binding the hostile Q P to his post.
13. 28.d4 At last!
14. 28…Be3 White resigns, for if (29) B x B, R (R 3) x P ch.; (30) K - Kt, R - Kt 7 checkmate.