Ever wonder how a national day of prayer and gratitude morphed into a carbo-load for the Black Friday shopping marathon? Put some of the blame on our own beloved Philadelphia. 

Philly held the first Thanksgiving Day parade in 1920.  The first parade was sponsored by the Gimbels department store.  Floats and marchers paraded down Market Street, with the finale being Santa entering the toy department at Gimbels.

Since then Thanksgiving and Christmas shopping have gone hand and hand with the attendant Black Friday hoopla acting as the official kickoff the shopping season.

In a special holiday podcast of That's History, historian Jonathan Zimmerman and host Dave Heller talk turkey and tradition and ponder the origins of turducken.

That's History is a biweekly radio segment co-produced by the Historical Society of Pennsylvania and WHYY featuring HSP historian Jonathan Zimmerman. That's History takes an event, issue or person in the news, and looks back into history for echoes, parallels, and lessons.