There is a chance of rain and temps will be in 50s and 60s in the romp through Britain's capital, and there would be more opportunities for classic urban exposure in London than in Nashville:
Psychogeography has become a popular term. It's the active exploration of urban areas. One definition is "a whole toy box full of playful, inventive strategies for exploring cities" and "just about anything that takes pedestrians off their predictable paths and jolts them into a new awareness of the urban landscape" ....Or does Nashville have its own hyperpsychogeography that might might shine through Saturday's wilting heat?
My solution - run, don't walk. Hyperpsychogeography, we might call it. And I think the organisers of the London marathon must have had hyperpsychogeography in mind when they planned the route.