Friday is the last day of open outcry futures trading on the floor of the Minneapolis Grain Exchange.
For more than a century, traders have gathered in what's known as the pit, shouting bids and offers back and forth in an auction system.
When the grain exchange first opened in downtown Minneapolis, the city had just surpassed St. Louis as the nation's leading producer of flour.
Now the shouting will end. Grain trading will continue, but the exchange is shifting to all-electonic futures trading. The Minneapolis exchange remains the nation's center for trading spring wheat, the variety of wheat grown in the Dakotas.
MPR's Perry Finelli talked with Dave Kenney, author of "The Grain Merchants: An Illustrated History of the Minneapolis Grain Exchange."