This week "Sunday Morning," hosted by Jane Pauley, features Mo Rocca's cover story examining what we didn't know about President Herbert Hoover. Plus: Lee Cowan talks with Martin Scorsese, Al Pacino and Robert De Niro about their first-ever collaboration, "The Irishman"; Anthony Mason looks at the life and music of Janis Joplin; Martha Teichner traces the life of abolitionist Harriet Tubman; Rita Braver visits an exhibition of works by abstract expressionist painter Helen Frankenthaler; and David Pogue finds himself trapped in an escape room – will he get out alive?