On the way from Berlin to Aachen, I had an 18-minute stopover in Cologne, whose name derives from the colony (colonia) that the Romans established here on the banks of the Rhine, their broad German frontier. As the train pulled across the mighty river into the station, a double-layered memory entered my mind: at some point in the 1980s, strolling the plaza in front of the cathedral, which is adjacent to the train station, I noticed a paving stone different from all the others around it, in that it was carved with the legend, in English:

THIS COULD BE A PLACE OF HISTORICAL IMPORTANCE

I don’t recall whether I was in the company of someone I loved back then, or on my own while in recovery from the ending of that relationship, or even with long-vanished friends; but I do recall that I thought it a witty take on the impossibility of clear and detailed historical knowledge, and at the same time an acknowledgement that any spot we stand on, unbeknown to us, could be significant in some sense: maybe an army assembled here as a general made a speech, maybe someone was murdered here for reasons falsely principled or petty, maybe two lovers met quietly here for their first tryst.

The second layer to the memory was that last year, on my way from Prague to Paris, I had similarly had to change trains in Cologne, but with a couple of hours to spare. I had spent much of that interval thoroughly combing the entire vicinity of the cathedral for the paving stone I remembered, without success, and had come to the conclusion that either the stone had been removed in the more than a quarter of a century since I had seen it, or that it had never been there in the first place; that I had made it all up, and that I was cleverer than I thought. But when I got home to Sharjah I had googled it, and yes, there it was – apparently one of a number placed at historical locations throughout Europe – just a few steps to the north-west of the cathedral doors.

That spot was much less than 18 minutes’ round trip from the station platform, so on the spur of the moment I decided to look again. The train disgorged its passengers, families and lovers meeting and greeting each other – this could be a place of historical importance – and I headed for the cathedral plaza. This time I found it with the minimum of searching. Here it is:

Now history twines in upon itself: for me, is this now a place of historical importance, binding together, through this photograph, vastly different decades of my life, the third and the sixth?

On my way back to the train I had enough time to buy and eat a Brie salad sandwich.