Maybe you’ve heard about the so-called “Scream Tunnel” at Wellesley College, and are wondering just what it is exactly.

It’s one of the most iconic of Boston Marathon’s many traditions—a quarter-mile of screaming students and fans, located around Mile 13 of the Marathon. There’s enough noise to hear it back for a quarter mile, though it’s not a tunnel in the strictest sense.

The tradition started with the first Boston Marathon in 1897. The college’s site explains:

The College is around the halfway point on the marathon route. In the first race, Wellesley students are reported to have cheered on a particular favorite (a Harvard student), thus setting a precedent for vociferous support for the runners.

The tradition appears to be just as strong as ever, with co-ed students screaming, waving and offering hugs and kisses of support to runners as they pass.

The tunnel is also known for its hundreds of signs held by fans to support the runners. Starting in 2011, students of Wellesley’s Munger Hall have taken sign requests, asking only for donations to help pay for the cost of making them. They’ve capped off this year at 400 signs, though they’ve done up to about 800 last year.

The signs are photographed and posted on Facebook as they make them. You can also follow the Scream Tunnel on Twitter.

Photo by ????? – Creative Commons (CC BY-SA 2.0).