Hosted by Jane Pauley. In our cover story, Ted Koppel explores how America appears ? to its allies and adversaries ? to be relinquishing its global leadership. Plus: Maurice DuBois interviews activists, writers and educators bearing witness to our national reckoning about racism, while The New Yorker magazine?s Kelefa Sanneh looks at the 1921 massacre of blacks in Tulsa, Okla.; David Martin discusses a new book about the first atomic bomb with its author, Fox News anchor Chris Wallace; Tony Dokoupil visits with "SNL" cast member Pete Davidson to chat about his new movie, "The King of Staten Island"; Mo Rocca explores the many ways Broadway talents are putting on a show even as stages go dark; and ?Sunday Morning? remembers the artist Christo, who became renowned for wrapping buildings and landscapes with colorful fabric to create monumental, transformative and yet impermanent works of public art.