Hosted by Jane Pauley. In our cover story, David Pogue explains the “heat dome” behind record-breaking temperatures. Also: Jane Pauley talks with actor Michael J. Fox about his Parkinson’s; Robert Costa interviews GOP presidential candidate Chris Christie, former governor of New Jersey; Elizabeth Palmer examines the threat to Taiwan’s democracy posed by nearby China; David Martin witnesses troops training in mine-clearing exercises; Martha Teichner visits a sanctuary for pet pigs; and Seth Doane takes to the water in a classic Italian Riva wooden motorboat. Source