Just ask the silver fox anchorman what it was like shooting Planet in Peril, the new four-hour environmental-issues series he did with Animal Planet host Jeff Corwin. The two, along with CNN's chief medical correspondent Dr. Sanjay Gupta, crossed four continents and 13 countries for the series, which debuts on CNN Tues., Oct. 23.

"What I really learned is you actually have to go into nature to report on the environment, which is sort of annoying...