Mariano Rivera became one of the most iconic relief pitchers in Major League Baseball history over a 19-year career spanning from 1995 to 2013.

The Hall of Famer came from pretty humble beginnings, and he made his baseball gloves out of cardboard in his native Panama, as Rivera demonstrates here:

As a seven-year-old, this was how Rivera made sure he had the equipment to play the game. And as he says to close off his tutorial, "this was the beginning of a Hall of Fame career."

Rivera has showcased his methods for constructing the makeshift glove before, previously discussing it with Brandon Steiner of Steiner Sports in 2011.

"I was the happiest kid in the neighborhood with this thing," Rivera said then, adding that he and his friends couldn't afford to buy a baseball or tennis ball, so they made balls out of netting and tape from the fishing village.

In 2019, Rivera became the first unanimous inductee to Cooperstown. He posted a 2.21 ERA while recording a major-league record 652 saves in 1,115 games.

His legend only grew in the postseason. Rivera finished his career with a 0.70 ERA and 42 saves over 141 playoff innings.

And it all started with a cardboard glove.