This morning, as I rode the U-Bahn south with my daughter on her way to school, we passed beneath the old dividing line in the city at Bernauer Straße almost at the moment the news headline flashed up on the television screens in the train carriage. As of today, the Berlin Wall has been history for more days than it ever existed; a site of memory longer than it was a dividing line written in concrete and defended by guards with guns. For 28 years, two months and 27 days it surrounded West Berlin and split the city in two; from that August day when barbed wire was rolled out along city streets to that November night when Berliners danced in the shadow of the Brandenburg Gate. The debate about what should be done with this symbol of a divided Germany began the very next morning.

Most of it was quickly removed. Memorials were erected to those who died attempting to cross the border and to other momentous events during those 28 years. The route of the Wall became the Mauerweg or Berlin Wall Trail, a waymarked hiking and cycling route running for 160 kilometres through the very heart of the city and out around the edge. Parts of the former security strip became parks and other public spaces. Some sections were gradually filled in as the city once more grew together. Yet other sections were returned to the forest, no longer offering any barrier to the deer and wild boar who cross the once-more invisible dividing line at will. In the past few years wolves have been spotted within Berlin’s city limits, for the first time in two centuries.

Over the past 28 years museums have opened and exhibitions have been held. On important dates in the calendar Berlin remembers the Wall and what it represented, both in its existence and in the dramatic way it came down. The Berlin Wall moves in and out of the collective imagination, depending on family histories, the time of the year or what is on our mind on any given day. People cross the line of cobblestones each morning without giving it another thought, while others go to an office by Alexanderplatz to read their Stasi files. Tourists congregate at Bernauer Straße, while Berliners ride their bikes along the path by the Tegeler Fließ. On Sundays they all come together, to pick over old Amiga records or visit the street food shacks at the Mauerpark flea market. For some it’s history, something that happened in another time, to other people. For others it remains a wound.

Ossis. Wessis. Das Volk. A whole generation has been born for whom the Berlin Wall existed only in the memories of their parents and grandparents. A school lesson or a film starring Tom Hanks. And yet spend any time in Berlin and it is possible to see how the legacy of the division continues to shape the cityscape even now the Wall has been down longer than it was ever up.

Since I moved to Berlin in early 2002, when the post-Wall era was entering those difficult teenage years, I have walked all 160 kilometres of the Mauerweg. Some parts only once. Other sections more times than I can possibly remember. I remain convinced that this is one of the best ways to understand not only the history but also its legacy. To read in the new building developments – and the debate that surrounds them – how the city has changed over 28 years and in which direction it is going. To think about how we remember the stories of the past, and how we choose to memorialise events both tragic and hopeful. To try and understand what those years of division meant for society on either side of the Wall, and how those experiences shape people’s ideas and attitudes today.

Today I am also thinking a lot about of my own memories. Of walks with friends through the city and along the lakes; beneath the skyscrapers of Potsdamer Platz and the silver birches of Frohnau. Of hearing stories of those who have become my family, who can remember crossing to West Berlin for the first time and on what they spent their welcome money. Of trying to explain these stories to my daughter, so that she understands the context in which her parents grew up; one in the GDR and the other among the cabbage fields of West Lancashire. And I think about the day I ran with a good friend all the way to Schönefeld along the trail, and how we will run the whole route together this summer as part of a relay that remembers those who lost their lives for simply wanting to do what my daughter does each day on her way to and from school.

History is everywhere in Berlin. Sometimes it feels like there are so many memorials, so many sites of memory and so many plaques in the wall and on the floor that it is easy to see none of them at all. Days like this, therefore, are useful to help us to notice and reflect on that line of cobblestones as we step across from one side to the other, and to remind us to think again about the stories of our city and what they represent.

I am running the annual Mauerweglauf as part of a relay team in August. Each year the race is dedicated to a person who lost their life at the Berlin Wall and the patron of the event is the former GDR civil rights activist Rainer Eppelmann. In 2017, the runners ran in memory of Dorit Schmiel. You can read her story at the Berlin Wall Memorial website here. In 2014, for the 25^th anniversary of the fall of the Wall, I co-wrote a book about stories from the Berlin Wall Trail with my friend Paul Sullivan. It was published by Slow Travel Berlin and you can buy copies via their website, where you can also book a place on my small group walks along the invisible border and hear some stories from the divided city.