BARRIERS are going up around Europe. Hours after a terrorist in a van mowed down pedestrians on Barcelona’s Las Ramblas last week, Madrid installed massive plant-pots at Puerta del Sol in the Spanish capital. Entrances to the Galleria Vittorio Emanuele, leading to Milan’s cathedral, are blocked by ugly new jerseys, as Italians call them – the modular concrete lane separators first used in the US state. Nice, victim of the worst vehicle attack to date, has only recently unveiled a white truck-resistant pillar-and-cable fence, cordoning off the Promenade des Anglais, where 86 people died on Bastille Day last year. London, hit by two attacks this year, has reinforced pedestrian walkways on bridges with concrete blocks. To the acute pain of further loss of innocent lives – tourists, shoppers, revellers – add the sinister, hard-to-define threat to something quintessentially European: the paseo, the passeggiata, the promenade. “Walkability” has become a central tenet of urban planning. One study suggests that people living in walkable places engage in 100 minutes more physical activity a week than those who don’t. “Walking meetings”, as favoured by the late Steve Jobs and Mark Zuckerberg, are now modish ways to stimulate creativity in Silicon Valley and beyond. But we Europeans do not need to be told by professors and entrepreneurs that walking is good for us. We have been strolling sociably towards greater wellbeing for centuries. Arriving in Barcelona in 1826, the American naval officer Alexander Slidell Mackenzie took rooms overlooking “the Rambla”. The street, built over an old riverbed and at that time only recently urbanised, was “constantly frequented by every variety of people, and in the afternoon was thronged to overflowing”, he wrote in his travelogue A Year in Spain. Well-dressed men and women mingled with peasants, artisans, French officers and their girlfriends, students, curates and monks. It goes without saying that the threat of imminent attack puts this tradition of ambulatory, open-air cosmopolitanism in jeopardy. The essence of the stroll – which, in Paris, gave birth to the ideal of the flâneur, the leisurely observer of city life – is that it should be relaxed. When I lived in Milan, which is certainly not Italy’s most laid back city, a passeggiata in one’s Sunday best, past the Galleria and the Duomo, was a weekly restatement of one’s part in civilised society. The menace of terrorism will have already persuaded some nervous boulevardiers to divert to less populous places, take the car, or cower on the sofa at home. For those who do venture out, having to keep an eye out for murderers in vans wrecks the whole idea of a civilised city walk as an exercise in stress-free people watching. It doesn’t do to romanticise the notion too much. These days, Las Ramblas is as much an overcrowded tourist attraction as a civic amenity. It has “evolved from being the favourite street of Barcelonans to a street many avoid”, Eduard Cabré, an urban planning consultant, told website Citylab shortly after the attacks. And of course, local authorities need to protect citizens from likely threats. Hence the new bollards on many of our boulevards. At the same time, though, “we really don’t want to abolish pedestrians or we will end up with ghost cities”, as Marialena Nikolopoulou of Kent School of Architecture told me. She and others have tested clever alternatives to fortifying public spaces, such as using mirrors or floor markings to make pedestrians act playfully, so that suspicious behaviour stands out. It is worth a try, if only to safeguard the public demonstration of civic sociability and friendly exchange so admired by generations of visitors. “Who can say enough in praise of the paseo?” Mackenzie wrote in the 1820s. “It furnishes an amusement at once delightful and innocent, and from which not even the poorest are excluded, a school where the public manners are softened and refined by social intercourse and mutual observation; where families meet families, and friends meet friends, as upon a neutral ground.” It is a measure of how hard terrorists have hit Europe that we now have to armour that innocent, neutral ground like a potential battlefield. Published in Daily Times, August 23rd 2017.