The main basin of Gloucester Docks in the fog, with a 'Dutch barge' moored in the foreground and Llanthony Road Bridge in the background.  This was on a cold and damp morning in January.  The fog was much thinner an hour later.
<a href="//commons.wikimedia.org/wiki/User:Tom_Axford_1" title="User:Tom Axford 1">Tom Axford 1</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>