The Berlin Wall, which as of Monday has been down for longer than it was up - 10,316 days - was a brilliant expression of the power of oppression.
It was vast, 155km long. It was frightening, laced with mines, dotted with soldiers trained to shoot first and ask no questions. It was also far more effective than any physical barrier could ever be because it produced what East Germans called "the wall in the head", the omnipresent belief that there was no escape, no hope.
So it struck Germans on both sides as nothing short of miraculous when the whole massive construction of concrete, bricks, barbed wire and electrified fence collapsed in what seemed like an instant.
I was the Washington Post's Berlin bureau chief in 1989 when the barrier that had divided communist East Germany from capitalist West Germany since 1961 finally fell. The history books say the Wall opened on one strange night in November of that year, but that's not quite right. It was really a process that took several months, a process that consisted of the physical deconstruction of the wall, countless changes in people's daily routines, and a mental shift that was perhaps the biggest hurdle of all.
Early one December morning, I was the first motorist queued up to pass through Checkpoint Charlie from East to West. While reporting a story in East Berlin, I had overstayed my visa - reporters were required to get out of the communist East by midnight or face arrest. Lacking the papers I would have needed to book a hotel room legally, I'd kept on reporting through the night, and now, as dawn approached, I could once again cross the border back into the West.
As the 6am reopening of the city's internal border approached, the East German guard who stood between me and a return to the West painstakingly set up his desk and went through his morning ritual of opening the gates. Finally, the Vopo - the Volkspolizei, or people's police, guards who never smiled and always managed to unnerve - flipped on the fluorescent bulb that hung over his traffic lane.
"And God said, 'Let there be light'," he said, breaking into a big smile.
I sat there in stunned silence. The fearsome Vopo had cracked a joke.
He laughed at his own wit. He looked to me for a reaction.
The internal calculations that become second nature in a police state took me a few seconds to run. Was this a trick? Do I laugh and get accused of disrespecting the people's police? Do I stare straight ahead and risk incurring the wrath of the all-powerful Volkspolizei? Eventually, with a slight, nervous grin, I looked him in the eye, something I'd once been warned against doing by a much sterner East German officer who'd caught me driving on a highway that was off-limits to westerners.
The border guard repeated his joke. This time, I allowed myself to smile along with him. He didn't even bother to check inside my trunk. Breaking a zillion rules, he just waved me through. The wall, the one he'd spent his working life defending, the one outside his booth and the one inside our heads, was gone.
In those weeks of startling change, every day brought new experiences. A few border crossings later, I was returning to the West after spending a day in an East German school where teachers were suddenly on their own, trying to figure out if they still had to teach the once-strictly required classes on communist ideology. I had tucked away deep in my luggage a piece of contraband, an East German high school history textbook, 800 pages detailing every action of each Communist Party Congress in the country's 40-year history. No party materials could cross the border - every time I'd tried before, the guards had confiscated everything.
This time, the guard found my book and chuckled as he flipped through it. "You can keep that," he said, "No one needs those anymore."
In those first weeks after the Wall was semi-officially opened, the East German regime tried to maintain its separation and independence from the West, but the people knew what their Government would take seven months to figure out: The game was up. In the final days before all border controls between the two Germanys were lifted, a few Vopo guards still insisted on checking travel documents. When one threatened to turn back a foreign visitor, the tourist loudly told a friend, "Don't worry, he's history in 10 days." The guard heard and replied softly, "Don't make fun."
On one of my last journeys through the controlled border, an East German guard went through the motions of stamping passports, but he could no longer muster the stern visages and menacing stares of the past. Instead, he chatted with us about his impending unemployment.
"It's all for fun now, but in a few days, no more job," he said. "Unemployed. I'm good at stamping things."
A police state, it turned out, was a matter of attitude as much as it was of concrete and sniper's nests. Germans on both sides of the divide would spend the months and decades that followed learning that the physical wall was far easier to dismantle than the barrier in their heads.
Superficially, the city changed almost instantly. Six months after the first easterners crossed freely through the wall, a new visitor appeared towering over the guard booths at Checkpoint Charlie: The Marlboro Man's 4.5m high image dominated the plaza where the Vopo had scared me into staying up all night.
But deep inside, the wall persisted.
Years later, I met a former border guard at a bar in the East. He'd never found another job. He wanted me to know that he'd never shot anyone at the border. He would have - that was what he'd been trained to do - but he'd never had the occasion. He said he still thought about it every day.