One of the pleasures of Oxford is walking across to Port Meadow, open grassland unploughed for 4000 years where cows cool their cloven hooves in the River Thames (known as the Isis here in Oxford) and people wild swim alongside swans and geese. Idyllic (except for the hundreds of teenagers). But we're mathematicians, so we have other watery things on our mind.
That Robin Wilson, he doesn't half go on.
To infinity in fact, the topic of Robin's eighteenth and final talk on the equations that made mathematics. With an irritating little paradox to whet your appetite below and the full talk here.