San Francisco International Terminal at night [File photo]

I do not know where the impulse to travel comes from but I have always had it bad since I was four or five.

A Vietnamese child living in the Mekong Delta, I remember listening to my French-educated father's stories of snow on the gilded bridges across the Seine; in the well-groomed parks of Paris; across his bunker's window when he was a military exchange cadet in Denver, Colorado, and on barren trees and moss-strewn rock gardens and temple roof-tops of fabled Kyoto.

I remember standing on tiptoe, afterwards, on a chair next to the opened fridge with my hands in the freezer compartment scraping at the frost until my fingers were numbed.

Even then, with eyes closed and a modest snowball in my palm, I had begun to travel; or perhaps I was trying to commune with my worldly father.

Travel stirs the imagination like nothing else. Away from home and hearth, ingesting in a new landscape, the traveller's concepts of his own identity, borders and nationhood are all up for dispute.

Today, Paris and Hanoi and New York are no longer fantasies but a matter of scheduling. My imagination, once bound by a singular sense of geography, expanded its reference points across the border towards a cosmopolitan possibility.

Indeed, we live now at a time when freedom of movement is recognized as a basic human right and the business of travel — hotels, transportations, tours, cruises, restaurants, conferences — has evolved to become the largest industry in the world. Tourism is the No. 1 source of foreign revenue for many countries (including the United States), employs more than 200 million people worldwide — about one in nine of all workers — and accounts for 11 per cent of all consumer spending.

Swift flow of information and border-less economies may be fusing globalization but the phenomenon is created in large part by the unprecedented movement of people. Here, in San Francisco where I now live, the international airport saw more people going through it each year than there are people living in the state of California.