From 2022, Jon Wertheim’s report on “preppers” who are gearing up for extreme catastrophes. From 2008, Scott Pelley’s visit to the “doomsday vault” inside a mountain near the North Pole, built to warehouse backup copies of all the world’s crops. From 2023, Pelley’s interviews with scientists who say the planet is in the midst of a sixth mass extinction with Earth’s wildlife running out of places to live. And also from 2023, Bill Whitaker’s story on virus hunters who are searching for new pathogens to help prevent another pandemic.