Four horseshoe-shaped concrete domes are planted on the slope. They form the base for the VI's Mortar Rack No. 65. Unique designed and large Artillery Battalion platform structure is apart of the Defense Outpost Line made by the Russian Empire in 1914-1918.
It is a extensive military base, that is apart of a crescent shaped outpost structure around the Helsinki Metropolitan area. More about history : http://www.rky.fi/read/asp/r_kohde_det.aspx?KOHDE_ID=1570
Terrain is really rocky, good shoes are required. Be careful on the site, trenches are some places pretty deep, danger to fall is possible.