April 15 not only is a historic date in Brooklyn and Los Angeles Dodgers franchise history, but it is celebrated across Major League Baseball as a whole, to commemorate Jackie Robison breaking the color barrier in 1947.
Days after signing with Brooklyn, Robinson immediately reported to the Dodgers for their Opening Day matchup against the Boston Braves. The crowd of 26,653 witnessed one of the most historically significant events in MLB history, as Robinson started at first base.
With his wife, Rachel, and son, Jackie Robinson Jr., in attendance, Robinson made his MLB debut and broke the color barrier.