Franco Harris, one of the most beloved NFL players of all time and a true Pittsburgh Steelers legend, sadly passed away at the age of 72. Harris, a nine-time Pro Bowler and a member of the Pro Football Hall of Fame, was involved in one of the most iconic plays in league history, the Immaculate Reception, a wild, last-second play that powered the Steelers to a playoff victory over the then-Oakland Raiders 50 years ago.

In honor of the memory of Franco Harris, let's take a trip down memory lane and revisit the Immaculate Reception, complete with a highlight video and explanation of one of the greatest moments in league history.

When: December 23, 1972

The scene is set in the third year following the AFL-NFL merger, with the Steelers taking on the Raiders in a regular season rematch in the divisional round of the postseason.

Where: Three Rivers Stadium, Pittsburgh, Pennsylvania

A multi-purpose field located in Pittsburgh, Pennsylvania. The stadium was home to the Pittsburgh Pirates and Steelers from 1970 to 2000. It was also home to Franco Harris' Immaculate Reception.

The Play: Franco Harris' Immaculate Reception, Explained 

The Steelers, who had made the playoffs just once in their franchise's history, were looking to change their fortunes against the Raiders, who had been to an AFL Championship game and a Super Bowl already.

The game started off with little work for the scoreboard operators, as the Steelers and Raiders took a scoreless tie into their respective locker rooms.

The Raiders found the end zone, with the Steelers settling for a pair of field goals in the second half, setting the stage for the Immaculate Reception play.

With the Steelers trailing 7-6 in the fourth quarter and 22 seconds remaining in the game, quarterback Terry Bradshaw dropped back to pass and the pocket quickly collapsed on him, forcing him to scramble to his right.

That's when chaos ensued.

Bradshaw looked downfield and tossed a pass to running back John Fuqua. The ball bounced off of Fuqua's helmet and every Steelers fan held their breath.

In the right place at the right time, Franco Harris scooped up the ball just before it touched the ground, running the ball all the way to the end zone- and the Steelers into football relevancy- in the process.

Franco Harris' amazing catch became the Immaculate Reception thanks to Pittsburgh sportscaster Myron Cope, who reported on the team's victory and used the phrase on air.

A local Pittsburgh woman had called Cope before his broadcast to suggest the name, which was coined by her friend.

It stuck- and Franco Harris' improbable Steelers play had a name.

Not only that, but it sparked a huge debate that exists to this day.

The back judge on the field raised his arms to signal a touchdown while the other members of the crew did not.

Raiders safety George Atkinson maintains that the ball hit the ground, among other infractions he said occurred during the Immaculate Reception play.

Raiders star Jack Tatum contended he never touched the ball, which would mean that Harris illegally touched the ball.

Harris himself added to the mystery of the play, saying he “can't say” whether or not the ball hit the ground.

Illegal or not, controversy and all, the referees made their decision on the field- and the Immaculate Reception forever became a part of NFL lore.

50 years later, the Steelers honored Franco Harris' Immaculate Reception on Friday night down to the very minute the play occurred, complete with the original radio call of the play, which blared through the Acrisure Stadium speakers.

During halftime of the Steelers' Week 16 game vs. the Las Vegas Raiders, the Steelers will retire Franco Harris' number.

Not only will it be a celebration of the Immaculate Reception moment, but also a celebration of the man who helped author the moment: Franco Harris.