This year's British Grand Prix was the first Formula One race since the start of the coronavirus pandemic to feature a full crowd, and by Sunday evening it showed. As 140,000 fans emptied the grandstands to join the long queue of traffic creeping out of the circuit, several tonnes of rubbish were left in their wake.
From beer cans to burger wrappers to event guides and lost sunglasses, much of the rubbish made its way into the bins dotted around the 3.2-mile racetrack but there was a lot was left in the grandstands. Cleaning up a mess like that is, and always has been, part of the deal when hosting 350,000 people over a three-day event. Football matches are similar, music festivals are often worse, but it's rare that one of the stars of the show gets involved in the clean-up operation.
Yet as the sun went down over the Silverstone circuit, four-time world champion Sebastian Vettel slipped on a pair of mechanic's gloves, a facemask, and grabbed a plastic bag to help pick up litter with a small group of fan volunteers for over three hours. The next day he followed the rubbish to the Grundon waste facility 65 miles away in Slough to learn about how it was recycled.
"It's not like a campaign or anything," he explained to ESPN when asked why he was pushing green issues more this year. "When it comes to picking stuff up, we can't do everything because that's not possible, but every time I am out running and I see something, I pick it up and put it in the bin or take it home and put it in the bin.
"I've noticed at the tracks there is a lot of stuff lying around after the races and I think it was a good opportunity, also for myself, to see the problem we are facing."
Racing in 23 locations around the world, Formula One usually arrives at its destination on a Thursday morning and leaves by Sunday evening. The fast-paced sport rarely has time to appreciate its surroundings, packing up what it needs at the end of the weekend and leaving what it doesn't. It's not uncommon for unopened champagne bottles to be handed to anyone with space in their checked luggage or, failing that, left behind at the circuit along with vast quantities of uneaten food and forgotten flower displays.
In recent years, F1 has recognised the need to clean up its act. A new focus has been put on sustainability, from reducing the amount of single-use plastic in the paddock to increasing the availability of green modes of transport to and from the track for fans.
However, it's clear that there's still a long way to go. For an operation where performance is prioritised above all else, convenience becomes addictive and waste is often a natural by-product. But, as the old saying goes, you have to start somewhere, and Vettel wanted to get a grasp of just how big the problem is across an entire race weekend.
"F1 is one event in probably a thousand that weekend, but it's obviously the event that is close to me," he said. "The reason [I did it] is clearly to communicate and show people that we can all make a difference.
"One thing is to realise the size of the problem that we all have ahead of us, and the second is to understand that we can all make a difference.
"It's quite sad if you don't think you can make a difference because you think you are too small, but if eight billion people decide they can make a difference then it's the biggest difference that can be made. So, basically, I'm just pushing that message."
It's easy to look at the professionally taken and carefully filtered photos of Vettel in the grandstands and assume it was a photo-op; a PR opportunity to improve the image of a multi-millionaire who's made his money in a gas-guzzling global sport. But Vettel isn't your average sports star.
The 34-year-old German is one of the least image-conscious drivers in Formula One. He is the only one who doesn't have a presence on social media and has made a very conscious effort throughout his career to divide his public life at the race track from his private life at home in Switzerland. If he has an ego, he hides it well.
While the majority of the drivers turn up to circuits in flashy hire cars, Vettel prefers to cycle, and at the most recent race in Hungary he was seen peddling through a thunderstorm on his way to the track on race day. In Austria, he dedicated some of his time ahead of the race to building a "bee hotel" with local school children to try to offer refuge for wild bees, whose numbers are dwindling across Europe. He followed that up by handing out packages of flower seeds to people in the paddock, so that they too could create bee-friendly environments back home.
And at a number of races he has been spotted in the paddock cleaning up plastic bottles left by TV crews, so seeing him cleaning up the grandstands at the British Grand Prix wasn't a huge surprise.
"It was not about taking a picture to look nice and to show off what I can do," Vettel said of the litter picking photos at Silverstone. "It was about getting our hands dirty, and we picked up the stuff and cleared two grandstands in three and a half hours, and made sure that it went to the right place
"The fact the grandstand was clear after we finished held the absolute priority over the pictures, but nowadays it's what you do and it allows you to share that moment with others and hopefully inspire other people.
"In the end I think it's crucial that we all communicate the problem that we are facing. Obviously, I can see that I have the potential to inspire a certain amount of people and if I inspire just one, then maybe that is enough -- maybe that's the background [of why I did it]."
For many people, the threat of climate change and the impact humans have on the environment seems incomprehensible and insurmountable. In isolation, Vettel's recycling drive at Silverstone and his bee hotel in Austria will not make a difference to the global situation, but he hopes they can snowball into having a bigger impact. With extreme weather caused by climate change impacting lives across the globe this year, including serious flooding in Vettel's home country of Germany this summer, he is keen to take action.
"I think one thing is to realise in what sort of situation we are in and the second is to understand there is no alternative," he adds. "It's not like this is just a trend and then we move on and go back to normal. This is our normal and it will only become more of a problem if we don't act.
"I think there is a chance that we can control this, but it takes all of us to be united. It's similar to the lines of what I said before, if you think you don't make a difference, you can then say what difference will Germany make or what difference will Formula One make? But if we all think like that, for sure, it is clear where we are headed."
The world's premier motor racing series may not seem like an obvious platform for promoting green issues, but sustainability forms a key part of its "We Race As One" initiative. The sport has pledged to have net-zero carbon emissions by 2030 and host more sustainable events by 2025, although Vettel believes it could be acting faster to really make a difference.
"Formula One has a huge chance because it is broadcasted every two weeks throughout the year -- nearly every week with more races coming -- we are racing in different countries and we should set the standard," he said. "There are some plans [for the future], great slogans, messages and ideas, but I don't know, honestly, if we have that much time.
"If Formula One gets so much credit for being so fast and having the fastest cars and technology, then we should do that [in terms of improving sustainability] and act fast and not just talk fast. So I think we can do a lot more than what we are doing.
"I think we should move fast and move forward, so in that regard there is plenty of stuff. In terms of the technology, the cars are at the front with the engine formula and the regulations, but we have big events and -- for a moment neglect the fact that we are racing cars -- in Silverstone there were 140,000 people just on Sunday and even more throughout the weekend.
"So it was a big event and it is a big opportunity to communicate and, I don't want to say educate, because it's not like 'we do this right and you should do this', but just to show people what can be done and to inspire, rather than pointing with the finger and saying you need to this or that."
One area Vettel hopes F1 can make a difference is in its plan to introduce sustainable fuel made entirely from bio waste in the next five years. The sport has always appealed to car manufacturers as a high-speed, high-profile R&D platform in which technology is developed on the track before filtering down to the road. However, F1's current V6 turbo-hybrid engines are in danger of being caught on the wrong side of automotive history as the majority of major manufacturers shift their R&D budgets into all-electric vehicles.
But Vettel, who is unlikely to still be racing when the next set of engine regulations are introduced in F1 in either 2025 or 2026, still believes the sport can burn fuel while developing technology that makes a significant difference.
"Well I think F1 needs to figure out what really makes sense in the future and where there is a chance to have the biggest impact on what matters in the future," he said. "Looking at the future of mobility, it will be a combination of things. I don't think it will be only electric, I think electric definitely deserves its place and is a great way to head into, but there are other things.
"Hydrogen is probably still a little bit far away but the potential seems to be there. I'm not a real expect and know too little to say more, but it's clear it [hydrogen power] is not plug and play and is not ready quite yet.
"But I am quite convinced that synthetic fuels will play a big role as long as you ensure the way you are making them is from renewable energy. Going forward we have to change, and whether that is only electric or a combination with hydrogen or something that will be invented in the next years, we need to be open to that.
"Looking at the wider picture, we still have a lot of cars on the planets, but we also have a lot of trucks and ships and airplanes, and I think for ships and airplanes you can't power them with batteries because of the size, packaging and weight. So you need to find a way to still operate them because people will still want to fly around the world and travel and have our goods shipped from one place to another.
"For that, I can see that Formula One has a huge potential. But for 2025 or 2026 if it is postponed, it still seems like quite a long time away if you think how quickly things need to be done.
"It's not easy to come up with a new engine or new regulations, but you could say that maybe two or three years ago we should have had that conversation and not now. But it is what it is, and it is better to tackle it right now rather than postpone it by another year or two."
Vettel may not race in F1 for many more seasons, but as he shifts his focus to wider issues away from the track he has the potential to be a guiding light for the sport's future.