<a href="//commons.wikimedia.org/wiki/Las_M%C3%A9dulas" title="Las Médulas">Las Médulas</a>, <a href="//commons.wikimedia.org/wiki/Province_of_Le%C3%B3n" class="mw-redirect" title="Province of León">Province of León</a>, <a href="//commons.wikimedia.org/wiki/Spain" class="mw-redirect" title="Spain">Spain</a>. Roman gold mine. UNESCO World heritage site.
Håkan Svensson (Xauxa)
CC BY 2.5
<span class="int-own-work" lang="en">Own work</span>