First there were marathons. Then came the onslaught of more extreme races: Ironmans, ultra-marathons, and 24-Hour Tough Mudders. Now there’s a race that sounds even more intense: the Earthathon, a 25,000-mile journey equivalent to one lap around the globe. In reality, it’s a group relay race intended for everyone from exercise newbies to seasoned athletes.

The premise is simple: Sign up, choose a team, and get running—or jogging or walking. After every workout, log your miles on Earthathon’s website to help your team get one step (or really a few miles) closer to the finish line, and share your accomplishment on Twitter using the hashtag #earthathon.

The social component of the race is huge. If you scroll through the hashtag you’ll see dozens of people cheering each other on and sharing personal tips and tricks. “It’s so wonderful to find a community who loves running as much as I do,” says Anna Borghesani, an Earthathon participant. “And we don’t just talk about running. It’s everything from baking to foam rolling.”

Dave Spencer, a runner from Washington, came up with the idea for Earthathon at a time when he didn’t have any races lined up. To keep himself motivated to run every day, he started a run streak (runner lingo for running at least one mile per day). On one of those runs, he started thinking how all of his miles could add up. How long would it take him to run the length of the continental United States? And then came the big question: How long would it take him to run across the world? After some quick math, Spencer realized it would take him years, even if he ran a dozen or more miles a day.

So he shared his quest with his running buddies on Twitter and slowly but surely convinced some of them to get on board. They launched the first Earthathon in September 2014 and completed it just before the end of the year. By the end of the race, hundreds of other runners from around the world had joined, so Spencer got the idea to split the participants into 10 teams for round two. Each team has its own theme, from #Runshine for runners who are all about happiness and positivity to #HeForSheRunners for people passionate about gender equality. The camaraderie and enthusiasm shared amongst team members is amazing, says Paul Layne, captain of #HeForSheRunners. “It’s the additional ammunition I need to go out and train for my upcoming races,” he says.

While there is some friendly competition to be the first team to reach 25,000 miles, Earthathon is ultimately about improving as an individual runner. Plus, once a team reaches the 25,000-mile mark, its members join other teams to help them reach the finish line (and so on until no teams are left). If you’re interested in joining the latest race, which kicked off the beginning of July, you can learn more and sign up here.