It is Vappu (Walpurgis day) - a traditional spring festival and one of the biggest holiday in Finland.
Celebration starts on the evening of 30 April and continues to 1 May. All upper seconday school get to wear the white cap and you can imagine how its white colour get a darker shade every year! I would imagine the darker/dirtier it gets, the more respect you get ;)
On 1 May, all generations party and picnic in the parks consuming sima (mead) and sparkling wine.
On Vappu's eve, I got to get together with a few friends and even though we have still cold weather it felt as summer is around the corner - maybe due to the buffet table's rainbow of colors and tastes.
Hyvää Vappua!
-c-