IN THE BUILDING opposite mine here in Ho Chi Minh City, still commonly called Saigon, an old man in the top-floor apartment tends his rooftop garden. He climbs there via a ladder every morning, shirtless and holding a plastic watering can, and spends a half hour amid green potted plants. I watch him shamelessly, a 31-year-old Australian Jimmy Stewart in a Vietnamese Rear Window. How old would he be? Old enough to have been in the war. He moves slowly, and pays no attention to me or anything else beyond his tended patch of green – in fact, he appears to be encouraging a wall of creepers to all but block out his view of the street.

But where he turns away, I want to look outward, to the street and the city. We’re close to a bus stop, and when I look away from him and down I can see, besides street stalls, motorbikes and general bustle, a steady trickle of well-dressed young people walking along dragging wheelie suitcases. If they’re heading towards the bus stop they’re typically diddling on their phones, and I imagine them calling up their confirmation itineraries. If they’re heading away from the bus stop, into the warren of narrow Saigonese alleyways, I can usually see airline baggage ties fluttering on their luggage. Where are they going, or where have they been? Study? Work? Tourism? They walk briskly, exuding a sense of purpose.