Sammallahdenmäki, about 25 kilometres northeast of Rauma, is a Bronze Age burial site and Finland's other UNESCO World Heritage entry in this corner of the country. The site consists of 33 granite cairns dating from roughly 1500 to 500 BCE, set on a forested ridge that was a sea-cliff in their time. The most striking are the so-called Church Floor — a long rectangular cairn unique in Scandinavia — and the Long Heap of Huilu, a 16-metre cairn that looks like a stone barrow.
The setting is the main draw alongside the cairns: pine forest, lichen-covered boulders, and silence. A signposted walking trail of about a kilometre loops through the site, with information panels in Finnish and English. There is a small car park but no facilities; bring water and good shoes. The cairns are at their most atmospheric in low autumn light or after a light snow.