What does Elvis Presley's 1956 appearance on the Ed Sullivan Show have in common with the 1901 assassination of William McKinley? And the onset of the Pequot War of 1637, for that matter? They are three of the 10 Days that Unexpectedly Changed America, as revisited in a History Channel series airing for five consecutive days starting Sunday at 9 pm/ET. (A detailed schedule appears at the bottom of this page.) To gain insight into this trip down memory lane, TVGuide.com spoke to acclaimed director Joe Berlinger (Metallica: Some Kind of Monster, Paradise Lost: The Child Murders at Robin Hood Hills), a coexecutive producer on the project who also helmed one of its installments.