Fresnel lenses at <a href="https://en.wikipedia.org/wiki/South_Stack" class="extiw" title="en:South Stack">South Stack</a> <a href="//commons.wikimedia.org/wiki/Lighthouse" title="Lighthouse">lighthouse</a> in <a href="//commons.wikimedia.org/wiki/Wales" class="mw-redirect" title="Wales">Wales</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/45614557@N00">Tim Herrick</a> from Sheffield, UK
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/45614557@N00/1116845081/">South Stacks lighthouse light and compass</a>