What moment does Ferren say changed his life?

His life changed when he went to see the Pantheon in Rome when he was 9 years old. Ferren was amazed with how the builders combined art and design with the science of engineering to make the building beautiful and functional 2,000 years ago.

Then, when I was about nine years old, we went to Rome. On one particularly hot summer day, we visited a drum-shaped building that from the outside was not particularly interesting. My dad said it was called the Pantheon, a temple for all of the gods. It didn't look all that special from the outside, as I said, but when we walked inside, I was immediately struck by three things: First of all, it was pleasantly cool despite the oppressive heat outside. It was very dark, the only source of light being an big open hole in the roof. Dad explained that this wasn't a big open hole, but it was called the oculus, an eye to the heavens. And there was something about this place, I didn't know why, that just felt special. As we walked to the center of the room, I looked up at the heavens through the oculus. This was the first church that I'd been to that provided an unrestricted view between God and man. But I wondered, what about when it rained? Dad may have called this an oculus, but it was, in fact, a big hole in the roof. I looked down and saw floor drains had been cut into the stone floor. As I became more accustomed to the dark, I was able to make out details of the floor and the surrounding walls. No big deal here, just the same statuary stuff that we'd seen all over Rome. In fact, it looked like the Appian Way marble salesman showed up with his sample book, showed it to Hadrian, and Hadrian said, "We'll take all of it." (Laughter)

But the ceiling was amazing. It looked like a Buckminster Fuller geodesic dome. I'd seen these before, and Bucky was friends with my dad. It was modern, high-tech, impressive, a huge 142-foot clear span which, not coincidentally, was exactly its height. I loved this place. It was really beautiful and unlike anything I'd ever seen before, so I asked my dad, "When was this built?" He said, "About 2,000 years ago." And I said, "No, I mean, the roof." You see, I assumed that this was a modern roof that had been put on because the original was destroyed in some long-past war. He said, "It's the original roof."

That moment changed my life, and I can remember it as if it were yesterday. For the first time, I realized people were smart 2,000 years ago. (Laughter) This had never crossed my mind. I mean, to me, the pyramids at Giza, we visited those the year before, and sure they're impressive, nice enough design, but look, give me an unlimited budget, 20,000 to 40,000 laborers, and about 10 to 20 years to cut and drag stone blocks across the countryside, and I'll build you pyramids too. But no amount of brute force gets you the dome of the Pantheon, not 2,000 years ago, nor today. And incidentally, it is still the largest unreinforced concrete dome that's ever been built. To build the Pantheon took some miracles. By miracles, I mean things that are technically barely possible, very high-risk, and might not be actually accomplishable at this moment in time, certainly not by you.