A postcard on aurora, a natural light display in the sky. It can be seen particularly in the high latitude (Arctic and Antarctic) regions. It was caused by the collision of energetic charged particles with atoms in the high altitude atmosphere (thermosphere). This picture is from Finland.Thanks Kettu.
A 2 kl/lk unusual shaped stamp with a vacuum and a 0,05€ stamp were used. It was sent as economy post. A parcel postmark (probably) from Oulu 90600 cancelled these stamps on 27.11.2012.