LINDA WERTHEIMER, host: This is the 100th anniversary of the discovery of Machu Picchu, the cloud city high in the Peruvian Andes, one of the most remarkable archeological sites on the planet; certainly the most incredible site in the New World. Now, of course, in Peru they say that it was not discovered a century ago today because Peruvians had never lost it. But we in the U.S. give credit to Hiram Bingham III, a remarkable and driven man who thought the Andes might be his last opportunity to make a great discovery.
MARK ADAMS: This was sort of the golden age of exploration. You know, at the moment Bingham got to Peru in 1911, Scott and Amundsen were camped out in Antarctica getting ready to race for the pole. So, he was going to make himself famous one way or another. When Who's Who came out, the 1910-1911 edition, even though Bingham was a lecturer in history at Yale, he identified himself as an explorer and he continued to do so for the rest of his life, even though he later became the governor of Connecticut and then senator from Connecticut.
WERTHEIMER: That's writer Mark Adams talking about Bingham. Adams has written a book called "Turn Right at Machu Picchu: Rediscovering the Lost City One Step at a Time." He joined us to talk about Hiram Bingham's journey and his own.
ADAMS: My "brilliant" - in quotes - idea was to retrace Bingham's route of his expedition in 1911, and that was a journey on which he wasn't actually looking for Machu Picchu. He was looking for another city called Vilcabamba. And while making this sort of circuitous route, he found Machu Picchu and two other almost equally impressive Inca sites.
WERTHEIMER: You had a guide, a wild man from Australia named John Lievers.
ADAMS: Yes, John Lievers. He's a throwback to the sort of pre-Lonely Planet era of travel. You know, when he's not leading trips in the Cusco area he's off exploring for pre-Colombian ruins that no one has ever recorded before.
WERTHEIMER: Could you read to us from page 92, and give us a little bit of the backstory, because you're not looking at Machu Picchu yet.
ADAMS: No, no. John and I are walking over one 5,000-foot-high mountain ridge after the other and we're actually on a four-day journey on which we didn't see any other trekkers at all.
WERTHEIMER: Now, you're at tremendous altitude.
ADAMS: Yeah, we're approaching 15,000 feet.
WERTHEIMER: OK. So, then what he wanted to show you was what is the called the Inca trail.
ADAMS: Exactly. This is an old part of the Inca trail, what was known as the Qhapaq Nan.
(Reading) This may be the finest stretch of original Inca trail left in all Peru, John said, as we crossed a small rise, looking down onto a path that snaked ahead of us like a miniature Great Wall of China. The road was beautifully engineered. The surface was elevated and paved with white stones. Masoned retaining walls on both sides protected the causeway from flooding. In the few spots where the trail had worn through, the deep and intricate foundation work laid down five centuries ago was evident; we were walking on a work of art.
WERTHEIMER: How did you get yourself into some kind of shape where you could walk up 5,000 feet just to take a look at a view?
ADAMS: Well, I thought I was in good enough shape when I arrived, but once we got on the trail John sort of disabused me of that idea. He would say things to me like, you know, Mark, your body's going to adapt through trauma.
WERTHEIMER: Oh great.
ADAMS: And when your body and mind are traumatized, that's when you'll adapt.
WERTHEIMER: And you were actually able to do this without dying.
ADAMS: Without dying, although I did have the mother's little helper of the Andes, which is coca leaf.
WERTHEIMER: Now, it's called coca but it's not cocaine.
ADAMS: No, no, no. It is the root ingredient of cocaine - it keeps your energy levels sort of steady while you're at altitude and it relieves what they call soroche, or altitude sickness, which is this horrible headache that comes on at high altitude.
WERTHEIMER: Now, when you were reading, you read about the extraordinary structure of the Inca trail. And I must say, I thought that one of the most interesting things that you talk about in this book is the way the Inca built those extraordinary structures.
ADAMS: Absolutely. The capital of Peru, Lima; the city of Cusco; they've both been leveled several times by earthquakes. But Machu Picchu, when Hiram Bingham got there 100 years ago, was still standing. And the reason for this was that the Incas used this incredible building technique where they would use hammer stones, which are these incredibly hard small stones that they would bounce off large pieces of granite, almost like they were playing jacks. And they would flake off little chips until they had the stones in the exact shape that they wanted and then fit them together as tightly as Legos. And this sort of, without any mortar in them, allows them - they call it dancing. So, if there's an earthquake, the buildings can dance. And Machu Picchu itself was built across two fault lines. So, you know, it's an area of a lot of seismic activity.
WERTHEIMER: Hiram Bingham's last expedition to Peru was intended to answer the great question of that place. Where do you end up on the question of what Machu Picchu is and what it's for?
ADAMS: I came to the realization that it's a country estate. Sure, that's great. But there's another theory that makes even more sense to me, which is that it was a sacred center. And if you stand in Machu Picchu, there are sacred mountains exactly to the north, south, east and west. There's a sacred river that wraps around the peak, almost encircles it like a python. And Machu Picchu sits at the point where the Andes hit the Amazon Basin. So, geologically and topographically, this is a really important piece of land. And I think the Incas built this as a truly sacred site. And one day a year, on June 21st, you can actually see the sun rise over a mountain to the east of Machu Picchu. And when it gets above the peak, it shoots a beam of light through a window in the Sun Temple at Machu Picchu, which is the most beautiful building there. And it forms this sort of rectangular shape on this slab of granite that almost looks like the base of a trophy where the trophy has been cracked off. But that cracked-off spot, that sort of missing chunk, that's what we don't know. What was there? I'd love to know what was there.
WERTHEIMER: Mark Adams' book is called "Turn Right at Machu Picchu." Mark Adams, thank you very much.
ADAMS: Thanks for having me.
WERTHEIMER: Read about Mark Adams's first meeting with his guide, John Lievers, in an excerpt from "Turn Right at Machu Picchu." It's on our website, NPR.org.