Underground wine caves in the Champagne where Champagne is aged in a constant cool temperature environment.
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/30291593@N00">giulio nepi</a>
CC BY 2.0
originally posted to <b><a href="//commons.wikimedia.org/wiki/Flickr" class="mw-redirect" title="Flickr">Flickr</a></b> as <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/30291593@N00/2166912864">Epernay Champagne Moet Chandon Cave</a>