I have swum a number of times at Runnymede, with the Swim The Thames Group, and across the years when two of my children went to Royal Holloway, University of London. It is a stunningly historical place to swim, with a real nod to modernity. Part of the front end of this swim involves going under the biggest bridge of the non-tidal Thames, and certainly the widest of the entire Thames. Fourteen lanes wide. The last time I swam under it, I was tired, having swum in excess of 5 kilometers, I was ready for tea, cake, any form of calories, so I didn't too much addition, beyond, 'it's wide, really wide'. This time, fresh and happy and filled with calories, I looked up, and what a cathedral it is. Juliet sang as she swam - what you can do when doing breaststroke! - and the acoustics were, just resonant, even if not designed with singing in mind. In fact, it's two bridges, older and new, amazing architecture, I felt in awe. This is not the usual senstaion when swimming under a bridge, but certainly one to remember. The swim took us through Staines, and on to (again) very historic Truss's Island. Thanks to Juliet for screengrabs from her filming of swimming under the M25. I am sure this is unique footage.