Formula One bosses say 100,000 people attended its London Live demo despite being given just two days' notice the event was going ahead.
The landmark show saw all 10 teams and every driver except Lewis Hamilton descend on central London for a demo from Trafalgar Square down to Whitehall and Horse Guards Parade. It is part of new owners Liberty Media's vision of turning every event into a Super Bowl-style extravaganza, with London Live originally being set up to promote this weekend's British Grand Prix.
Though the event was several months in the making, it was kept secret by organisers and media until two days beforehand due to concerns over logistics and security following recent terrorist attacks in London. As well as a host of demo runs from F1 cars old and new, it included a live stage at Trafalgar Square which operated from midday onwards and live performances from UK musical acts Bastille, Little Mix and the Kaiser Chiefs.
The success of London Live is likely to encourage Liberty to continue pushing for similar events in other cities. ESPN understands Liberty is in talks with at least one other major global city about a second big demonstration ahead of a grand prix in the second half of the 2017 calendar.
Sean Bratches, F1's new managing director of commercial operations, says the success of the event shows how far the sport has come since Liberty's takeover was completed in January.
"F1 Live London is the most striking example yet of Formula 1's evolution this year. We feel there is no better way to celebrate the exciting season we have had so far than to have this landmark event in London on the eve of the British Grand Prix.
"This is all about giving our fans the opportunity to get closer to the teams, cars and drivers they love. The day was a great success for London and F1 and we could not have done this without the help of all the London authorities, the Mayor's office, Westminster City Council, the Metropolitan Police and the other emergency services.
"But our biggest thanks goes to Londoners, those who turned up, those who followed events via social media and those who showed great patience if delayed on their way home. Thanks all for your support and understanding in showing once more why London is the sporting capital of the world."