Nadine's Restaurant (Pittsburgh, Pa.) •Casamento's Restaurant (New Orleans, La.) • Big Mama's Kitchen & Catering (Omaha, Neb.)Guy Fieri uncovers three joints puttin' a piece of history on the table: In New Orleans, an oyster bar where nothin's changed since 1919 and the deep fried oysters are still hand-shucked; in Pittsburg, a neighborhood 'dive' where Mama Nadine's dishin' up roast beef smothered in gravy and in Nebraska, Big Mama's cookin' her Grandma's soul food in an old school cafeteria.