It’s April 15–Tax Day for most Americans. For Major League Baseball fans, it’s a date to celebrate one of the game’s biggest heroes.

It was 79 years ago today that Jackie Robinson first took the field for the Brooklyn Dodgers, becoming the first Black player to suit up in the majors in baseball’s modern era. Robinson’s ascension to the majors, facilitated by Dodgers president and general manager Branch Rickey, ushered in a new era for the sport, with his play on the field and his poise in the face of racism from both fans and players on other teams paving the way for subsequent generations of Black players.

Robinson retired in 1957, having led the National League in batting and stolen bases in seasons during his career, and was named baseball’s Most Valuable Player in 1949. He was inducted into the Hall of Fame in 1962, his first year of eligibility. He died in 1972. Baseball started celebrating a day in his honor in 2004; five years later, it began the tradition of every player in the majors wearing the number 42 on April 15. All 30 teams will observe that tradition today.

Besides that, each team has its own individual commemorations planned. The league launched a new ad campaign, called “We Are Jackie”, highlighting the legend’s career. It will play in every home team’s ballpark today.

Robinson’s team, the Los Angeles Dodgers (they relocated the year after Robinson retired), will hand out commemorative No. 42 jerseys to fans before their game against the New York Mets. In Seattle, the Mariners will wear replica jerseys from the Seattle Steelheads of the Negro Leagues in honor of both Robinson, who played Negro League baseball, and the Steelheads’ 1946 team. The Mariners also made a $500,000 donation to the Steelheads Community Fund, which supports Black baseball initiatives in the local community.

The Baltimore Orioles are making a $10,000 donation to the Jackie Robinson Foundation, while the St. Louis Cardinals are contributing $40,000 to the foundation for college scholarships.

A complete list of MLB Jackie Robinson Day celebrations and initiatives is here.