64 years ago today, on July 25th, 1956 a baseball miracle took place before a sparse crowd at Forbes Field.

In his sophomore year with the Pittsburgh Pirates​, Roberto Clemente came to bat with the bases loaded, nobody out, and his team trailing the Chicago Cubs​ 8-5 in the bottom of the ninth at Forbes Field. He faced pitcher Jim Brosnan.

As the Pittsburgh Post-Gazette reported:
"Brosnan made one pitch, high and inside. Clemente drove it against the light standard in left field. Jim King had backed up to make the catch but it was over his head.

The ball bounced off the slanted side of the fencing and rolled along the cinder path to center field.

Here came Hank Foiles, Bill Virdon and then Dick Cole, heading home and making it easily.

Then came Clemente into third. Bobby Bragan had his hands up-stretched to hold up his outfielder.

The relay was coming in from Solly Drake. But around third came Clemente and down the home path. He made it just in front of the relay from Ernie Banks.

He slid, missed the plate, then reached back to rest his hand on the rubber with the ninth run in a 9-8 victory as the crowd of 12,431 went goofy with excitement."

Little did the crowd know but the play that ended the Pirates-Cubs game on July 25, 1956. was, in fact, the ONLY walk-off, inside-the-park grand slam in baseball history.

An excerpt from http://lithub.com/the-greatest-forgotten-home-run-of-all-time/