Flying into Hanoi's Noi Bai airport, the Vietnam countryside below lies as in a geography book illustration - paddy fields and tall, narrow houses. Motoring into the city, there is the reality: burgeoning modern infrastructure alongside traditional buildings and French classical architecture, a beguiling mixture lending the city its charm.
However, at Hoan Kiem Lake in the city centre, remembering the bombing during the "American" War, it dawns that, for a generation of teenagers in the 1960s, the only image we had of Hanoi was a name and a dot on a black and white map. Long before the digital news-gathering age, we had access only to pictures that the military or the government permitted, and while Saigon and points south featured on our screens, the country north of the demilitarised zone seldom did.
Of course, events nearer home were televised, but it seems strangely the case that our memories of that decade, and in particular the pivotal year of 1968, are frozen in the immediacy of black and white still photography, rather than moving pictures.
Those of us of a certain age have a permanent exhibition in our heads: the associates of Martin Luther King pointing from a motel balcony towards the direction of the shots that killed their leader; Robert Kennedy, the senator from New York, fatally wounded on the floor of a Los Angeles hotel kitchen while a bellboy presses rosary beads into his hand (pictured); a police horse rearing up before Grosvenor Square protestors; a hippy girl placing a flower in the rifle barrel of a blank-faced marine at the railings of the White House; marchers at Burntollet Bridge in Ireland bloodied and confused; and, in a Paris street, serious-faced students wearing hard hats behind a barricade, the CRS riot squad approaching and, in a quintessentially romantic moment, two of the students locked in a passionate embrace.
Decades and years can attract easy labels and lazy soubriquets: the Sixties are swinging and 1968 will always be the year of revolution. That decade, and in particular, that year, have been held responsible for practically every subsequent social movement from promiscuity to Thatcherism. But perhaps the most pertinent question - and the only one that really can be answered - relates to how it affected those of us who lived through it.
As a 16-year-old, I was certainly excited by the pictures and by what I read and heard. From the White House to the Elysee Palace, it was clear that the establishment was, at the very least, disconcerted by the explosion of "youth" in all its many guises. We argued with our parents and teachers and we wanted "change" but, mostly, we did our homework and listened to our music. What exactly we wanted to change, and how we would achieve it, was never quite clear.
So did those heady times leave a permanent impression, or were they as transient in our development as the changing fashions in clothes and music?
Age gives perspective, of course, and looking back makes answers, of a kind, possible. I have been lucky enough to travel widely, and in my destinations I think I detect a thread of connection to 1968.
I have stood by a simple white cross on a hillside in Arlington Cemetery and pondered what might have been had Bobby Kennedy, rather than Richard Nixon, made it to the White House. I have stood by a gable end in Derry's Bogside and thought about the march from civil rights through war to peace process. In Paris, in cafes by the Sorbonne, I have discussed whether philosophy and belief can really make a difference. As Barak Obama stands for the presidency, I remember sitting on the steps of the Lincoln memorial in Washington DC and hearing the words of Martin Luther King's "I have a Dream" still echoing down the years.
In Hanoi, Hue, and Da Nang, I reflected on the warmth and welcome of the Vietnamese people who had been invisible to most of the Western media during the war.
And in the last month, surrounded by a fantastic staff and a superb group of students at our senior prom, I recalled that the Orange paper, which launched the school guidance system and formalised a whole new approach to education, made its debut in 1968.
When I look at that journey - professional and personal, geographical and philosophical - I realise that the connection to, and the inspiration of, 1968 lies in the simple fact of humanity. The events of that year set me on a life course, not necessarily of revolution in its narrowest sense, but of prioritising humanity in my personal and professional dealings.
That's not a bad legacy for any year, and not a bad year to have been 16. The only scary part is realising it all happened 40 years ago.
Sean McPartlin is depute head of St Margaret's Academy in Livingston.