We stayed in London overnight, having gone to the late 'Spaghetti Western Prom' - and so we walked over to the Serpentine in order to watch the women's 10km Marathon swim in the Olympic test event. The event was a women's race, consisting of 6 laps of the Serpentine in Hyde park, 10km of swimming. The Men's race took place in the afternoon (though we would miss it, as we were to see the Beach Volleyball). Floating marker buoys indicated the route, and boats went alongside the swimmers.
A lot of people, it seemed, were unaware of the event, and out for their saturday morning strolls, or simply feeding the ducks. Though we watched the event, I found it all a bit low-key, it was very hard to follow what was happening from the south side of the lake. I didn't find it the most spectator friendly event.
We did walk around the lake, and found a big screen on the north side, but by then, most of the race had been completed - and besides, one might prefer the south side - extra screens, visible from the far banks would have been a good addition.