They say you should never argue with an engineer because - like wrestling with a pig in the mud - after a few hours you will realise he actually likes it. If there's another thing that engineers absolutely adore, it's Katse Dam.
This structure is guaranteed to bring tears to the eyes of the most unemotional engineer. And after visiting the massive dam recently, I won't argue with them.
Katse is probably the most underrated and undiscovered tourist attraction in southern Africa. It's not too easy getting there, but well worth the effort.
Katse Dam is in Lesotho, a mere 137km along a new tarred road from the border post at Ficksburg, the quaint Free State town famous for its annual cherry festival. The dam is either the biggest or second biggest in Africa (some claim it is the biggest, others say a dam in Ghana is larger).
The centrepiece of the Lesotho Highlands Water Project, Katse's flooded valleys extend for 45km and the dam wall is a staggering 185m high. Its waters feed the Vaal Dam which, in turn, feed the taps in your kitchen and bathroom. That's been happening since January 1998 - fairly easily, too, because the water's flow is aided by gravity through 4m-diameter tunnels leading from one of the world's highest kingdoms.
I left Ficksburg early on a mid-summer morning, planning to spend most of the day at Katse. After all, it was less than 140km to get there, and that should take me no more than 90 minutes, I thought. I had been told that the road to the dam is in excellent condition, but that I should be on the lookout for falling rocks.
What my sources failed to mention was the gradient. Some reports I read later suggested that it is as much as 40° - scary, when you think that the average sedan, such as my 1400 Corolla, tends to find any gradient higher than 45° a bit too much to handle.
The formalities at the somewhat informal border post were a breeze and, initially, making my way through a few villages where potholes slowed progress a bit, I still anticipated getting to Katse relatively quickly.
Eventually, I reached the new tarred road to the dam and started climbing, and climbing; and turning, and turning (there were often just about 20m between turns) for what turned out to be three challenging mountain passes.
Lesotho, they say, is not for sissies, and when you drive these roads you'd better believe it. Not for nothing is one of the mountain passes here called "God Help Me Pass". The passes - one of which is 2 650m above sea level - wind their way through magnificent scenery that would take passengers' breath away. Passengers, not the driver, who was too petrified to even glance sideways for a minute as the Corolla seemed to drive right into the clouds at the top of the mountain. After a bright sunny morning in Ficksburg, headlights were now needed to scale the heights.
It was amazing to think that thousands of heavy trucks had to climb these challenging mountain passes daily to bring building materials for the construction of Katse in the 1990s. A single truck - carrying 30 tons of dry bulk cement - had to negotiate the passes every 20 minutes, day and night.
At the end of the project, there were so many trucks and materials on hand that it took three years to dispose of them on auction.
Mercifully, for me, the road was quiet that morning, so it was mainly a case of avoiding the unnerving drops into space on the open side of the pass, while still keeping a fairly heavy foot on the accelerator to maintain momentum.
Years of towing a caravan up Du Toit's Kloof in days gone by stood me in good stead. But if my wife had been with me, she would have made me turn back to Ficksburg immediately.
Eventually the sun broke through, the road became straighter and the Lesotho I knew of old returned.
The lone horsemen with their distinctive Basotho hats and blankets, the pack mules carrying incredible loads (one was bearing what looked like an entire tree), the kids in what are now psychedelically coloured gumboots: little boys in pink wellies, would you believe? Eventually it was possible to stop and admire the scenery the waterfalls cascading from mountain tops, the terraced fields down the steep hillside, the stone-walled huts with straw roofs in the valleys below. And air so pure it almost hurts to breathe it.
But, being Lesotho, you can't stop for long before the empty countryside suddenly produces kids of all ages, arms outstretched, wanting "s-w-e-e-t-s". When planning a motoring holiday in Lesotho, you need a supply of sweets as much as a tank filled with fuel (you don't find petrol pumps around every corner in this part of the world).
Then, just about four long hours after leaving Ficksburg, there it was: the first arms of Katse Dam. The combination of huge, scenic, winding lakes set against the green mountains of Lesotho conjured visions of the lochs of Scotland. Katse is not one huge expanse of water; it consists of large stretches of deep water - with very low evaporation rate - which flow for kilometres over the Lesotho countryside.
It's a photographer's dream landscape but I couldn't help thinking of the thousands of Basotho who were uprooted from their homes, farmland and vegetable gardens to make way for the dam. More than 27 000 are apparently still awaiting the promised compensation.
But it is impossible to think about politics when you see the Katse Dam wall for the first time.
Now it was clear why my engineer friends get misty-eyed and return to the dam as if on a crusade to a holy place.
Gazing from the visitors' centre on a hill overlooking the dam wall, the sheer size and scope of Katse are overwhelming.
That 185m-high, 710m-wide wall assumed Tower of Babel proportions even from my lofty bird's-eye view: the teeth in the huge spillway cast a monster shadow on the wall and the relatively small outflow into a plunge pool at the time made me wonder what it would look like to see 6 200 cubic metres of water spilling through 10 overflow bays - each 16m wide - when all the sluices are opened. Apparently, the spray rising into the air rivals that at Victoria Falls.
After an informative presentation at the visitors' centre, our guide escorted us through passages in the innards of the dam wall: the control rooms from where the emergency and control sluices are operated; the inspection and drainage galleries; and equipment for measuring stress and seepage in the wall. A bewildering array of hydraulics, dials, lights and switches.
Even without the slightest understanding of what engineering is all about, you can't help but be impressed by Katse.
This incredible dam should rank with the major tourist attractions in southern Africa.
"See, I knew you'd be impressed," a man - clearly an engineer - said to his wife and children, who until then had perhaps wondered why they ended up in Lesotho for the December holidays while other Gautengers were frolicking on the beach at Margate.
The wide-eyed little boy opened his mouth in wonder. All that came out was: "Geeez "