New York Mets first baseman Lucas Duda (21) is all...

New York Mets first baseman Lucas Duda (21) is all smiles as he high-fives New York Mets centerfielder Yoenis Cespedes (52) after his three-run home run in the first inning during Game 4 of the NLCS against the Chicago Cubs at Wrigley Field on Wednesday, Oct. 21, 2015. Credit: Newsday / William Perlman

For most of the sports world, 1961 was a long time ago. There was no Super Bowl and no Michael Jordan, neither of whom had been born yet. There were six teams in the NHL and eight in the NBA.

But in the world of baseball, famous for its traditions and long history, 1961 was just yesterday. Sort of.

You see, after many years with eight teams in the American League and eight in the National League, that was when MLB expanded at last, adding the Los Angeles Angels and Washington Senators to the AL.

A year later, the Mets and Houston Colt .45s joined the NL. In 1969, the Royals and Seattle Pilots were added to the AL, with the Montreal Expos and San Diego Padres entering the NL.

Here is the amazing, somewhat mind-boggling thing about all that as it relates to the 2015 World Series:

The Mets-Royals matchup is the first in the history of the Fall Classic to feature two teams from MLB's expansion era.

In other words, it took until 2015 for there to be a World Series pitting two franchises that did not exist when the first Series was played in 1903.

Some of those old teams moved and changed names during that period, of course. And even among the expansion teams, the Colt .45s are now the American League Astros, the Pilots are the National League's Milwaukee Brewers, the Senators have become the Texas Rangers and the Expos are now the Washington Nationals.

That's baseball. But even though the Mets and Royals have remained in the same cities with the same names for roughly a half-century apiece, they remain relatively new kids on the block -- and the first to meet when it matters most.