Photo: kallerna, CC BY-SA 3.0 via Wikimedia Commons
Niinisalo garrison features some military functionalism. One of the barracks (Lamellikasarmi) from 1935 designed by Kalle Lehtovuori and the hospital from 1937 are built in functionalist style. As this is a military area, the buildings can't be visited just like that. Garrisons in Finland training conscripts do have open days twice a year (usually in February and August), other times of the year you might be able to catch a glimpse of the Lamellikasarmi from the northern gate, and you could try to contact the army if they would allow you in.