Wow. I would say -- let me just back up and say that generally the job of investigative reporting is mostly about getting up to speed as quickly as possible about really complicated topics, and then communicating what you've learned in readable prose in as short a time period as possible. So the biggest challenge is when you have the hardest, most complex subjects. After the 2008 crash I was given a general assignment to explain what happened, and since I knew nothing about Wall Street, I basically had to learn about ten years' worth of financial practices in the space of maybe eight weeks. Those early stories about Goldman and AIG were both thrilling and terrifying because it was so much to digest.

Another fun one (in retrospect) - I don't know if this is investigative journalism exactly, but I was once involved with what in hindsight was a very crazy caper: a Russian newspaper called "Stringer," for whom I worked occasionally, had a contact who was willing to sell them a week of wiretapped phone calls from Putin's chief of staff, Alexander Voloshin. I ended up doing the writeup of that story. There were some minor improprieties exposed in the transcripts, but nothing world-shaking. Still, I was so terrified about publishing it that I left the country. And when I returned, I was detained at Sheremetyevo airport for hours. It turned out the problem was an unlamented passport page. I thought I was going to prison forever.