If you were on the Red Line over the weekend, you may have noticed a few riders forgot to put on their pants. The annual No Pants Subway Ride made its way from from Rogers Park to the Loop on Sunday, as a small group of participants rode the train in their underwear—in spite of the cold winter weather. Occurring every January, the event is part of an international happening organized by performance art group Improv Everywhere. After a few weeks of brutal temperatures, it's the kind of lighthearted (and pantsless) fun that nearly every Chicagoan can appreciate. If you didn't witness it in person, take a look at our photos from Chicago's 2018 No Pants Subway Ride.