Chess is a game played between two players using 32 pieces (16 each of two distinct colors) on a square grid of 64 squares.
The earliest known ancestor of modern chess was an Indian game called Chaturanga, where the knight, King, and Rooks moved the same, but there was no castling or two square move for the pawn, and the Bishop and Queen were much weaker. It then moved to Persia where it was known as Chatrang, eventually making its way through the still-youthful Islamic Empire, where it was known as Shatranj, into Southern Spain. By the 1500's it had spread all through Europe and there were many different ways to play, including one where both King and Queen could move at the same time. The modern rules were adopted in Spain, and later the rest of Europe, sometime in the 1500's.
Legend has it that the Queen's power on the chess board was the idea of Spanish chess players, modeling it after Queen Isabella, arguably one of the most powerful female monarchs in European History.
Chess has been acknowledged as a sport by more than 100 countries. FIDE (Fédération Internationale des échecs) is the third largest sporting body in the world (behind the IOC and FIFA), has a delegate to the IOC, and may be in the Olympics sometime soon, making Chess one of the most popular sports in the world.