Thank you Terhi for this postcard! Originally on an inlet, this 1km long cluster of over 30 granite Bronze Age burial cairns are near what remains of this ancient inlet, now a lake 15km inland. Despite this landscape change, the vegetation is markedly unchanged, and many cairns remain unexcavated, giving the visitor, I can imagine, a memorable experience. 
Is the image on the left stamp possibly the stone wall which surrounds the cairn known as 'the long ruin of Huilu' (Huilun pitka raunio), excavated in 1891. Issued: September 8 2004.