Egg-section sewer in the Victorian sewer system of Brighton, East Sussex. In the narrow part of the tunnel the flow speed increases thus preventing sediment.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/61132483@N00">Les Chatfield</a> from Brighton, England
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/61132483@N00/219204360/">Egg shaped sewer . ..</a>