Chess puzzle (Checkmate)
Moves: 1. Nf3 c5 2. d4 e6 3. e4 cxd4 4. Qxd4 Nc6 5. Qd1 Nf6 6. Nc3 Bb4 7. Bd3 Bxc3+ 8.
bxc3 Qa5 9. Bd2 d5 10. c4 Qd8 11. cxd5 exd5 12. exd5 Nxd5 13. Qe2+ Qe7 14.
Qxe7+ Ndxe7 15. O-O O-O 16. Rfe1 a5 17. Ng5 g6 18. Nf3 Bg4 19. Ne5 Nxe5 20.
Rxe5 Nc6 21. Rb5 Bc8 22. Be4 a4 23. Rab1 Re8 24. Bxc6 bxc6 25. Rc5 Re2 26. Be3
Rb8 27. Rxb8 *
Position (FEN): 1Rb3k1/5p1p/2p3p1/2R5/p7/4B3/P1P1rPPP/6K1 b - - 0 27
Black to move.
Themes:  Endgame Back Rank Mate, Mate in 1 
Puzzle rating: 568
Best move: Re1#