One evening, I saw one of the strange spheres myself, close up. In all honesty, I had long prepared myself for such an encounter. Everyone I had spoken to had said that when they did appear, the balls became dazzlingly bright and it was impossible to make out any kind of detail in the glare. For months, I did my best to be around the growing structure on fine nights when, if the reports were to be believed, it was most likely the strange spheres would appear, and I never ventured onto the bridge after nightfall without a pair of dark goggles - the kind intended for welding - strapped to my forehead.

As the glow appeared and brightened - this one was a brilliant blue - and while others around me threw up their arms to protect themselves from the glare, I dropped my clipboard and yanked down the goggles over my eyes. I could see nothing except the brilliantly glowing sphere a few metres away, but I could make out some details within the ball.

It was not the swirling maelstrom of energetic plasma that my reading of the literature had led me to expect. Instead, there was a suggestion of a sphere of polished metal set with brilliant points of lights, each barely tolerable even with the heavily-tinted glasses. Squinting, I could just see between the individual lights, darker spots and complex patterns on the surface of the metal, and even the suggestion of movement as if bands of the sphere were turning relative to each other.

Perhaps this one was slower to move, for some reason, or perhaps it was just my overwrought senses which made it seem as if time had slowed down for a moment. In my fevered state, I was able to study what I could only take to be a machine of some kind, some kind of remote-controlled drone whose purpose I could not immediately guess at.

Whatever it was, within a few moments it accelerated away, disappearing into the darkness of the night made doubly so by the smoked glass goggles I was wearing. I saw nothing more, my vision smeared by the after-effects of the dazzling light and my mind dazed by the implications of what I had just witnessed.

Over the next couple of days, I wrote a report, describing in as much detail as I could remember every aspect of the encounter, and including sketches and diagrams of the flying machine as I remembered it. I also added my ill-formed speculations on what the device was and what its purpose might be. This report was, I now believe, ignored and unread, because by the time it was received something much more important had happened.

One of the cables snapped. Yes, one of the impossibly-strong, many-times overrated carbon nanotube cables had broken in the middle.

My return to the day-job of bridge architecture was abrupt and unforgivingly focussed. I returned to my offices and my computers, and went over all my calculations with a fine-toothed comb. I re-ran my simulations and had my colleagues, and indeed independent design professionals, check over the design with extreme care. All these inspections failed to find any error or inconsistency, and showed if anything that I had included rather more margin for error and safety than would have been normal.

A sample of the cable which had failed, and others from the same and different batches from the manufacturer, were stress-tested by an independent laboratory, one of the very few in the world owning machinery capable of applying the immense forces required to fracture full-size bridge supports. All the samples performed perfectly, remaining stiff and strong up to stress levels several times that of the requirements of the bridge design then flowing plastically before catastrophic failure.

I inspected the broken ends of the cable myself, both the pieces from the bridge and those fractured by the German test machines. There was little point: the energy required to break chemical bonds of this kind is immense and the breakage would have sent razor-sharp splinters flying outwards with the force of an explosion.

The preliminary report concluded that the cables were prone to undetectable flaws, a premise hotly contested by the manufacturer and supported, increasingly vehemently, by myself. I had great faith in the integrity of the cables and the physics underpinning their design.

All to no avail. I was removed from the project, my professional competence questioned and my integrity compromised. I was thought to have gone rogue. I had little choice: I resigned from my company and from my profession, while another architect was employed to start a re-design from first principles using the traditional materials of steel and concrete, materials which seemed to me as primitive as mud bricks reinforced with straw.

Part 5 Part 7