The Great Nocturnal Happening will be celebrated next time on Thursday, 5 August 2021. 
The participation form will open on this page in May 2021. 

The Great Nocturnal Happening (Tapahtumien Yö in Finnish) is a lively, carnival-like event that presents a wide range of shows, exhibitions and other adventures produced by various organizations, associations and performers around the town. The total of over 200 events are spread across the city, the first ones beginning early in the morning and the festivities continue late into the night.