Yesterday, I rose at 4 a.m. and took a taxi to London’s Heathrow Airport. This is not an uncommon thing for me to have to do. However, I must have been a little more awake than usual, as I started to pay attention to much more than I normally would on the drive to the airport.

At 5 a.m., London’s streets are far from deserted. In Shrewsbury, one of the places where I grew up, this would have passed for a busy morning, but for London, it was quiet. People were walking everywhere. At 5 a.m., there were queues at bus stops, some with ten or more people waiting. There were far more twenty-four-hour shops than I had imagined (why isn’t there one near me?), along with plenty of road sweepers and street cleaners—people generally keeping the city running for the rest of us who usually wake up later in the morning.

I worked a milk round when I was younger. I am used to people being up and about in the still hours before most wake. This, however, was different. It was busy and, in places, bustling. Seeing a few people on the streets at that hour would not have been remarkable, but seeing so many was startling.

When you walk home late at night and see buildings still lit, you imagine that, just like you, they will soon settle into a dark sleep. Yet, as we sped through West London, I was struck by the number of buildings—offices and shops—with all their lights blazing. Many were shut but fully illuminated, as though some invisible nocturnal customers were going about their shopping. Offices glowed as if an army of nighttime workers were invisibly seated at terminals, turning the wheels of trade. When walking home late at night, this seems normal, yet in the early hours before dawn, it feels eerie.

Most unusually, there was a market stall selling, I think, fruit and vegetables. It was open and well-lit on one of the main roads heading westwards. I cannot imagine there was much trade, yet the stall was stocked, illuminated, and ready for the occasional passing customer. Who is the strange stallholder who works the dark hours, sitting by the street waiting for customers to buy his fruits? Shouldn’t he have been at New Covent Garden collecting his goods at that time, rather than sitting on a cold A-road with no passing trade?

Then there was the man pasting new advertising billboards. At 5:15 a.m., he was atop his ladder with a bucket of sticky stuff, gluing a new poster for the morning commuters to see on their way into the City. I had always imagined these were changed in the mid-afternoon, not in the middle of the night. It must have been far too cold to be doing that job.

There is a whole world I am not familiar with. It’s really quite strange to come face-to-face with a city you do not recognise.