This is both a day and date anniversary, 11/05/11 saw the last boat from the Stroud valley through the tunnel and to, was it Cirencester - with a load of bricks.
Added to the "On this day" database ...and more pictures of the tunnel at
https://www.cotswoldcanals.net/sapperton-canal-tunnel.php... and I note that the opening of Sapperton Tunnel is the very earliest event we have "On this Day" - all 430 listed in chronological order
(here) through to the last day of the through Bristol to Waterloo service on 10th December 2021