First World War shelter room tunnel entrance in trench in base III:9 in [Krepost Sveaborg](https://en.wikipedia.org/wiki/Krepost_Sveaborg) land front defense line in Rajakylä, Vantaa, Finland. The base was built in 1915 - 1918. There is also [a model](https://skfb.ly/6SnWF) for another entrance to this tunnel.
The whole base contains:
* 135 meters of thrench
* 3 machine gun positions
* 2 observations posts
* 12 shelter rooms, one 35 m² room is inside a rock in tunnel
* 110 m² cave
More info:
* [Location in Google Maps](https://goo.gl/maps/duEN1zb8HHBVqjiZ8)
* [Wikipedia: Krepost Sveaborg](https://en.wikipedia.org/wiki/Krepost_Sveaborg)
* [John Lagerstedt , Markku Saari: Krepost Sveaborg](http://www.novision.fi/viapori/eavaus.htm)
* [Finnish Heritage Agency site info](https://www.kyppi.fi/to.aspx?id=112.1000007726) (only in finnish)