What is the Chicago Cubs' billy goat curse?

Chicago Cubs starting pitcher Jake Arrieta throws during the first inning of Game 2 .

(CNN)Until this year, the Chicago Cubs hadn't made a World Series appearance in a very long time.

In 1945, Dizzy Gillespie was tearing up the music charts with "Salt Peanuts," Time Magazine's "Man of the Year" was President Harry S. Truman, and World War II was coming to an end.
The Major League Baseball team was about to be blighted by the billy goat curse.
Legend has it a Chicago tavern owner named Bill "Billy Goat" Sianis pronounced a curse on the club on October 6 -- just a couple months after the end of the war.
    Sianis went to Wrigley to cheer on his beloved Cubs against the Detroit Tigers in the Fall Classic, according to the tavern website, which dedicates a page to the curse.
    For Game 4, he purchased a ticket for himself and one for his pet goat Murphy, thinking it would bring the Cubs luck.
    But ushers stopped Sianis from entering with Murphy. Sianis appealed directly to then club owner P.K. Wrigley, asking him why he couldn't take his personal mascot to the game.
    "Because the goat stinks," Wrigley replied, according to the Billy Goat Tavern.
    So Sianis threw his arms up and cursed the team.
    "The Cubs ain't gonna win no more!" he declared.
    When the Cubs lost the series to the Tigers, Sianis sent Wrigley a telegram.
    "Who stinks now?" it read.
    The Cubs were never the same again. Over the years, ghoulish pranksters left dead goats at the stadium. They became known as the "Lovable Losers." A popular Chicago T-shirt reads, "What did Jesus say to the Cubs? Don't do anything till I get back."
    Last year, the Cubs won 97 games. In the National League Championship Series, however, they were swept by a New York Mets team that won 90.
    And who could forget the eighth inning of Game 6 of the 2003 NLCS between the Cubs and Florida Marlins?
    The Cubs led 3-0. They were just five outs away from their first trip to the World Series since 1945.
    Then a lifelong Cubs fan named Steve Bartman, seated down the left field line, reached for a foul ball. He tipped the ball away from the outstretched glove of leaping Cubs outfielder Moises Alou. His interference was the catalyst for a heartbreaking Marlins rally and eventual series win.
    But that is all in the past.
    Oh, but back to the billy goat curse. The kids on the Chicago team believe that memory should be baa-nished.