Electric generator ( diesel engine and alternator ) installed in the underground worksite of the Coupole d'Helfaut in 1944, making the site autonomous in energy terms.
<a href="//commons.wikimedia.org/wiki/User:Vassil" title="User:Vassil">Vassil</a>
2011-10-28
<span class="int-own-work" lang="en">Own work</span>