Chess Tactic of Destiny!
Here is the position that changed the entire outcome of the Berlin Candidates Tournament. If Kramnik found the right continuation, he would have been +3 and we may have seen a completely different winner. However, Kramnik missed it and Caruana capitalized on it and won the game. He never looked back.
White to move. How should white proceed?
Kramnik v Caruana (round 4 of Berlin Candidates)