The Brazilian Immortal

In this game, the immortal, Joao Vianna, faces off against A Silvestre de Barros in the game we call the Brazilian Immortal. It's name comes from a series of stunning moves that leaves Black's defective position vulnerable to a hurricane of possible fatalities. As soon as Black plays 23...Kg8, Roberto Grau commented that "right now, Caldas Vianna finds a notable move, of problem, which creates many difficulties for Silvestre; study [this] position, before continuing with the reading, to see if you find the idea of the master; white pieces must take advantage of the defective position of the black King; the first check can be fatal for the black pieces; and this allows Caldas Vianna do the following beautiful move". 

Did you guys find the move? Well, the correct answer is 24. Nd6! where the Knight "protects the Q, who cannot be captured, because after 24...Qxb7 25.Nxb7, the White gains a piece; Black cannot do 24...Rxd6 because 25.Re8# ; black cannot take the P because 25.Qd5 or 25.Qf7#; black Q cannot take the white N: 25.Qb3+ Qd4 26.Qxd4 Rxd4 27.Re8# ; thus, there is a perfect spiral of mates born of the unpleasant situation of the black King. But, in fact, white pieces want to give a check with the Q in d5, and, therefore, pose a barrier to the Knight"--Roberto Grau. Well, after this series, White just has a firm command over the board and it didn't take much more to finish him off.