The sound arrived before the machines: a high, staccato rattle that, as an Associated Press correspondent noted in 1950, once made downtown Rome resemble the Indianapolis 500. On Saturday morning, that same insectoid chorus swelled again as a column of Vespas – 25,000 by organisers’ count – poured from the Baths of Caracalla and began its slow, buzzing pilgrimage through the city’s imperial core. Natalie Dunand, a French retiree marking her 61st birthday, sat astride her scooter with a West Highland terrier clipped cool behind her. “The passion for Vespa is for the Italian style, freedom, the ’60s,” she said, a sentiment repeated in a dozen languages along the parade route.

What followed was the largest gathering in the scooter’s eight-decade history, a four-day festival that transformed the Foro Italico into a Vespa village and drew riders from Kuwait, the Philippines, Australia’s Gold Coast and a Tokyo father who balanced his eight-year-old daughter on the seat while swapping club banners with an Italian enthusiast. The parade itself was a tightly choreographed affair: Rome’s local police deployed 130 officers to close roads progressively, reopening them minutes after the last two-wheeler had passed, limiting disruption to little more than an hour. Yet the visual impact was outsized – a technicolour ribbon of pressed steel, chrome and enamel paint unspooling past the Arch of Titus, the Altare della Patria and the Bocca della Verità.

The Vespa was born of industrial improvisation. In 1946, with the Pontedera factory in ruins, aircraft manufacturer Piaggio tasked helicopter engineer Corradino D’Ascanio with designing a cheap, mass-market vehicle. D’Ascanio, who reportedly loathed motorcycles, produced a machine with a load-bearing pressed-steel body, a handlebar-mounted gearshift and a skirt-friendly step-through frame. When Enrico Piaggio saw the prototype, its narrow waist and buzzing 98cc engine reminded him of a wasp – vespa in Italian. The name stuck, and the scooter quickly became a motor of Italy’s post-war recovery, putting a nation on wheels at a price of 55,000 lire, roughly five months’ wages for a factory worker.

Cinema gave the Vespa its global mythology. In William Wyler’s 1953 film Roman Holiday, Gregory Peck and Audrey Hepburn darted through the city on a faro basso model, and sales jumped 30 per cent in Italy and 50 per cent abroad. Since then, the scooter has appeared in more than a thousand films, from La Dolce Vita to Luca, accumulating a cultural weight that Piaggio has carefully managed. At the Stadio dei Marmi, a photo retrospective showed not only bikini-clad beach escapes but also explorer Soren Nielsen reaching the Arctic Circle on a Vespa in 1963. The brand, as marketing executive Davide Zanolini put it, has always had “a very charming attitude … much more of a lady than a man.”

Among the crowd, that charm translated into a peculiar form of soft power. A German visitor displayed a tattoo of the Vespa logo on his calf, framed by the words “La Dolce Vita.” Andrew Walton, a 59-year-old truck driver from Newcastle, had spent eight days riding from the Netherlands along the Rhine to reach Rome, drawn by the machine’s simplicity: “You get on, twist, go.” The gathering was as much a trade fair as a pilgrimage, with limited-edition helmets and Vespa-branded blankets on sale, but the dominant currency was nostalgia – for a time many participants had never lived through. As the last scooters disappeared into the Roman afternoon, the hum faded, leaving the cobblestones to the heat and the memory of a wasp swarm that had, for a few hours, made the ancient city feel like a film set from its own cinematic past.