Tic-Tac-Toe is a simple and popular two-player game played on a 3x3 grid. Players take turns marking a cell in the grid with their symbol (X or O). The goal is to be the first player to align three of their symbols horizontally, vertically, or diagonally. If all cells are filled without a winning alignment, the game ends in a draw. It is a classic game that encourages strategic thinking and is easy to learn.