A former shot tower in Pispala, Tampere, Finland.  Built in 1908, it was operational until some time in 1972.
<a href="//commons.wikimedia.org/wiki/User:Methem" title="User:Methem">Methem</a> (Mikko J. Putkonen)
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>