>> CATHY: LET'S JUMP RIGHT IN TO THE HISTORY SECTION OF TONIGHT'S SHOW.

LAST WEEK WE DUG IN TO THE MINNESOTA INVENTION FILE.

WE WERE LOOKING FOR A NEW PRODUCT THAT WAS CREATED BY A MINNESOTA COMPANY IN RESPONSE TO A DISCOVERY MADE DURING WORLD WAR II.

THE FIRST VERSION WAS INTRODUCED IN 1947.

IT MARKED THE BEGINNING OF A WHOLE NEW INDUSTRY.

OUR QUESTION TO YOU... WHAT WAS INVENTED BY A MINNESOTA COMPANY IN 1947 IN RESPONSE TO A DISCOVERY MADE DURING WORLD WAR II?

WE START, AS ALWAYS, WITH A QUARTET OF WRONG ANSWERS.

>> CATHY: NOPE, NOPE, NOPE, AND NOPE.

THOUGH THE PRODUCERS MAY LOOK INTO SOME OF THESE INVENTIONS FOR FUTURE INDEX FILE EFFORTS.

FOR THIS WEEK'S CORRECT ANSWER, WE TURN TO RON FROM EAGAN.

>> CATHY: YES!

3M AUDIO TAPE IS THE INVENTION WE SOUGHT.

AS RON NOTED, DURING WORLD WAR II, THE U.S. MILITARY DISCOVERED GERMANS WERE RECORDING AUDIO ON SOMETHING CALLED A MAGNETOPHONE.

ONE OF THE DEVICES WAS BROUGHT TO THE U.S. 3M WAS ENLISTED TO CREATE TAPE TO USE, AND THE MAGNETIC AUDIO TAPE INDUSTRY WAS BORN.

BING CROSBY WAS THE FIRST U.S. RADIO STAR TO PRE-RECORD HIS SHOW, AND HE DID IT WITH 3M TAPE IN 1947.

THOSE BIG REEL TO REEL TAPE MACHINES.

THANKS TO 3M FOR THIS FINE-LOOKING PHOTO.

BEFORE WE GO, HAPPY 97 BIRTHDAY TO BETTY ESKOLA.

WE'RE GOING TO HONOR THIS FINNISH GALLON WITH OPPORTUNITIES BY STUDENTS FROM THE CENTER OF IRISH MUSIC.

DON'T FORGET TO CHECK OUT THE IRISH FAIR OF MINNESOTA NEXT WEEKEND ON HARRIET ISLAND HERE IN ST. PAUL.

SEE YA LATER.

♪♪ [FAST-PACED IRISH MUSIC]