Have you ever fallen in love and realized that the "love" you thought you′d felt before was just a crush? Gone for a run with a new friend and realized that all the "running" you′d done before was only jogging?

All these years on Build It Bigger, I′ve been making a big deal about the dangers of being high up on some construction site. Hey, it felt pretty dangerous to me! But our shoot at the Mponeng gold mine in South Africa taught me what danger really means.

We were there because of the incredible engineering involved in digging deeper under the earth than anyone has ever dug. South Africa has certainly done more than its share of digging—its economy and its history are completely enmeshed in the mining of gold and diamonds. Fifty percent of the world′s gold reserves are found there still. But at the immense Mponeng mine, most of the accessible gold—down to two miles under the surface—has been mined already. Mponeng mine, which is the world′s more productive gold mine, is scheduled to close in seven years . . . unless they can dig even deeper.

By digging of course I mean drilling and blasting. Blasting further and further down, the heat and pressure rising with every foot.  With every blast, the energy from the explosion disperse into the rock, which means constant small earthquakes—and constant danger of collapsing rock.

All of this takes place at a barely imaginable distance from safety. To get down to the work site, we rode in open steel cages, a stack of three with about forty of us in each one.  It′s the longest elevator in the world, moving at 45 miles an hour, and our ears popped continually to adjust to the pressure. When we got to the bottom, we drove a land cruiser under the surface, downhill, for a couple of miles. Then we took a train. For an hour and a half we traveled away from the cages that could return us to the surface of the earth. If something went wrong, there′d be no way to get back up.

And things do go wrong. People are killed in mines all the time, more than a hundred last year in South Africa alone (much more than a hundred, depending on who′s counting). Two died at Mponeng just last month after we left. 

The danger—real and constant—is something we felt during our entire visit. On skyscraper sites, there′s some joking around about the safety precautions, some teasing of those of us who have a totally rational reluctance to be far from solid ground. And lots of celebration among the construction crew when they achieve something that′s never been done before.

At the mine, though, the tone was serious. They are working at the deepest occupiable point on planet Earth, and every day they set a new record. But no one is slapping high-fives about that. They are just happy to surface alive at the end of each day.

I was too. And then I had the surreal experience of actually pouring the liquid gold into bars—4 million dollars worth—for the privilege of which I was stripped, searched, guarded, surveilled, and temporarily locked up.

Serious business that makes you think hard about wealth and risk and human life. And makes you yearn for the relative safety of a half-built suspension bridge.