Impenetrable. They had used the word many times when they told the architect what they wanted. But that was wrong. The word they should have been using to describe what they wanted, was inescapable.
What resulted was something of a silo, sunken down into the ground and extending for hundreds of levels. 12 inches of concrete reinforced with titanium made up the outer walls. The inner walls were half the thickness, but still made of concrete, it was black on the outside, but once encased in sand it made little difference. It was located somewhere far out in the Nevada desert; nobody knew where it was except for the pilots of the black helicopters that came and went frequently.
The speed of the work on the building was astounding. It took just three years to build the whole thing, with multiple teams of workmen building around the clock. Helicopters constantly came and went like clockwork every three hours, dropping off new workmen to start their shifts and picking up those who were clocking off, flying them back to the nearby base camp, where the thousands of workmen had to stay due to the confidential nature of the project.
The architect too, stayed back at the base camp. He worked alone, contracted as such, but rewarded handsomely for the hard work. Usually, such an ambitious project would require a team of architects, but the contractors had insisted that he was the only one. A man in his forties, with an outstanding reputation as one of the best architects of the era, he had been approached by representatives from the government and taken the contract without having any information aside from a number. It was a very large number.
They had requested an impenetrable tower, with a thousand cells inside. There were superfluous details as well, a sleeping quarters, an armoury, a control room. The building they wanted was a prison. The architect was allowed to ask no questions that didn't immediately result from his design of the building, but the truth was that he didn't want to. With the amount they were paying him, he could afford to retire much earlier and much more wealthy, and so questions such as 'why' didn't bother him. He didn't care.
When he flew out to the desert to survey the site, they had excavated a giant crater in the sand. Falling from the edge would have resulted in broken bones, at the very least. It was like a gateway into Hell, the people on the bed of the crater looked like insects.
Halfway through the project, he had been approached again. Someone up the chain of command had decided that capacity needed to be tripled. There needed to be a much higher number of cells in the prison. Perhaps they were expecting a larger influx of prisoners than they had originally anticipated or perhaps they were transferring some. He didn't question, as per the agreement; he just added to the design, and carried on.
The whole operation was painfully clandestine. He could have no contact with family or friends while he worked on the project. No-one was to know where he was and he had no access to phones or the internet. People were blindfolded when the helicopters took them from the base camp to the site, and back. Searched thoroughly before boarding the helicopters either way, and heavily armed guards littered the construction site. It all made him feel very uneasy.
Finally, after painstaking work and man hours to rival those of every city in every civilised country on the planet since the dawn of time, the prison was completed. The crater was filled in by sky cranes dumping thousands of tonnes of sand around the structure, closing it in. The black monstrosity was locked in its sandy tomb, only a helipad on the top and an entrance were left visible. It was as if the construction had never taken place. And as far as the government were concerned, they'd soon erase every trace of it.

The National Defence Authorisation Act allows the US government to detain indefinitely without trial and without charge, anyone suspected of committing or aiding terrorism on American soil. These people do not have to be recorded as official arrests, and some will never see the light of day again. They simply disappear, as if they never existed.

The rotor blades cut through the air overhead as the Hessian sack scratched the skin on his face. His knees hurt from kneeling on the hard ground and the handcuffs chafed his wrists red raw. The rocking of the helicopter would have forced the architect to fall over, had there not been a rope tied around his neck, connected to the ceiling of the vehicle. Just tight enough to hold him in place, but not enough to cause any damage. He couldn't see, but he could feel the soldiers all sat around him, there was a taste of metal in the air. Cordite from the bullets of their rifles. Radio chatter crackled vaguely in the pilot's section. The helicopter touched down on the ground, sending sand into the air in cyclones. The soldiers suddenly became active, the architect's rope was cut and he was thrown from the vehicle onto the ground outside. He was dragged down corridors and through elevators seemingly forever, until finally, he was in a dark room, alone with one soldier, who ripped the sack from his head and unlocked his handcuffs. The architect made to run, but the soldier kicked him in the ribs and calmly walked out of the cell, slamming the door shut behind him and locking the architect into pitch blackness as he writhed in pain.
"Welcome to Dark Tower, you terrorist piece of shit."