If you’re anywhere near Lappis, the student housing area of Stockholm, on Tuesdays at 10 p.m. sharp, you’ll hear a chorus of screams. It’ll sound as though you’re trapped within a horror movie. In reality, it’s the cries of stressed students echoing through the air.

The life of a student can be hard and taxing, especially during exam seasons when the deadlines start piling up and the testing schedule seems like it’ll never end. Often, people want to scream and shout their frustrations out. Fortunately for the students living in Lappis, they get a chance to do just this every week.

Anyone in the area is welcome to join in on the Tuesday night shouting, but only at the designated time. Starting a shout on other days or times will usually result in angry students telling you to keep quiet.

The origin of the tradition is unknown. However, it was likely inspired by the Flogstra Scream that occurs each night in Uppsala. Shrieking into the night seems to be a quirky part of Sweden’s student life. It certainly adds a chilling touch to the long winter days.