Plenty of people have run it, and even more have cheered them on.

That’s right: the Marine Corps Marathon is taking place on Sunday, marking its return after a two-year in-person hiatus due to the COVID-19 pandemic.

The marathon is in its 47th year, though the last two years were run virtually. It attracts around 30,000 runners from all over the country and the world, making it one of the largest 26.2 mile races.

It starts by Arlington National Cemetery, goes up to Rosslyn and across the Key Bridge to Georgetown, after which runners must complete a roughly 16-mile circuit in D.C. that includes Rock Creek Parkway, Hains Point, and the National Mall, before sending them back across the Memorial Bridge to the finish in Virginia.

That means roads in parts of Arlington and D.C. will be closed ahead of the marathon’s 8 a.m. start, with some not reopening until late in the afternoon. The course map is here, the exact schedule of the road closures in Arlington County is here, and the D.C. road closure schedule is here.