Somewhere, I'm not sure where now, I'd picked up a brochure about this and then promptly forgot about it until yesterday. Then it became a matter of rush, rush, rush, as the installation closes at the end of tomorrow.
River Sounding is worth a visit for two reasons. Firstly it's a fascinating look at the Thames through video and sound. Secondly it allows you access to the Lightwells and the Deadhouse; below ground level parts of Somerset House not usually publicly accessible. The Deadhouse, alone, is worth exploring just for the memorial stones to various 17th Century luminaries.
The installation itself - 'A journey through the hidden sound worlds of the River Thames' - uses video footage of the river, bridges, the mechanism of Tower Bridge and buoys. These are displayed on the brick walls of coal holes. Sound comes from strategically placed speakers with the water augmented by bells, clocks and other mechanisms. It's a hypnotic, entrancing experience.
More info here.
