Incomplete 48 m² cave in First World War base XXXV:4 in [Krepost Sveaborg](https://en.wikipedia.org/wiki/Krepost_Sveaborg) land front defense line in Reimarla, Helsinki, Finland. The base was built in 1915 - 1918.
The whole base contains:
* 45 meters of thrench
* 2 observation positions
* 2 machine gun positions
* At least 5 shelter rooms
* 48 m² cave
More info:
* [Location in Google Maps](https://goo.gl/maps/X3pKNohzipc82Tfi6)
* [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=112.1000013909) (only in finnish)