Two teams of nine, a pitcher, a catcher a batter, three strikes and you're out, three outs and the other team gets to bat, nine innings in a game ... we're all familiar with the rules of America's pastime. But on June 26, 1944, the Dodgers, Giants and Yankees put a twist in those rules so that all three of New York City's teams could play each other at the Polo Grounds in one game.

It's been affectionately dubbed the "Tri-Cornered Game."

Just 20 days prior to that afternoon, Allied forces landed on the shores of France in the D-Day invasion. Tickets to the Tri-Cornered Game were $50 and $100 War Bonds. Each inning featured three parts as a Columbia University math professor orchestrated a rotation that called for the teams to cycle between batting, fielding and resting.

The game raised nearly $4.5 million as the Dodgers beat the Yankees and shutout the Giants in a 5-1-0 win over six frames. Mel Ott started for the Giants, Babe Ruth was supposed to appear (but didn't) and 50,000 fans got to experience a once-in-a-lifetime baseball event while helping their country.

U-S-A! U-S-A! U-S-A!