California Chrome, right, won the Preakness race last month. It will be exciting if he does the same at the Belmont Stakes. (John McDonnell/The Washington Post)

Something may happen Saturday that hasn’t happened in sports for 36 years. A horse may win the Triple Crown.

The three most important races for 3-year-old horses are the Kentucky Derby, the Preakness and the Belmont Stakes. If a horse wins all three races, it wins the Triple Crown.

California Chrome has won the first two races and is the favorite to win Saturday’s Belmont Stakes in New York. But winning the Triple Crown is tough. Only 11 horses have done it. No horse has won the Triple Crown since Affirmed did it in 1978.

There are lots of things in sports that haven’t happened for a long time. Some have never happened. Let’s take a look.

The Grand Slam in tennis is when a player wins the four biggest tournaments — Wimbledon and the Australian, French and United States opens — in one year. The last woman to do that was Steffi Graf in 1988. The last man to accomplish it was Rod Laver in 1969.

Golf has its own Grand Slam. A player has to win the four biggest tournaments — the Masters, the United States Open, the British Open and the PGA Championship — in one year. No man has done that, but Tiger Woods came closest: He won the four big competitions in a row, but only three of them in the same year: the United States Open, the British Open and the PGA in 2000, followed by the Masters in 2001. Folks called it the “Tiger Slam.” Women golfers have a Grand Slam with a different set of tournaments. No one has managed to win them all in one year.

In baseball, the poor Chicago Cubs have not won a World Series since 1908. That’s more than a century!

No Washington baseball team has won the World Series since the old Senators won in 1924. Of course, Washington has an excuse: The city didn’t have a baseball team for 33 seasons: 1972 to 2005.

Speaking of baseball, no batter has finished a season with a batting average as high as .400 (a .300 average almost certainly makes you an All-Star) since 1941. That year, Ted Williams hit .406 for the Boston Red Sox.

Washington Redskins fans complain that their team has not won the Super Bowl since 1992. An unlucky 13 National Football League teams have never won the Super Bowl, which was first played in 1967. Four NFL teams — the Cleveland Browns, Jacksonville Jaguars, Detroit Lions and Houston Texans — have never even played in the big game.

Of course, most teams and players never win the ultimate prize. (For example, 24 of the 32 teams in this year’s World Cup have never won soccer’s biggest trophy.) That’s why it’s super exciting when something that hasn’t happened for a long time in sports finally does happen.

So watch the Belmont Stakes and root for California Chrome. You might not see another Triple Crown winner for a long, long time.

Bowen writes the sports opinion column for KidsPost. He is the author of 19 sports books for kids including “No Easy Way: The Story of Ted Williams and the Last .400 Season.”