(from 24 March 2020) https://www.bbc.co.uk/news/health-51674743

(10 Mar 23) https://www.spectator.co.uk/article/sweden-covid-and-excess-deaths-a-look-at-the-data/

20 seconds a (25m) length is a bit too fast (maybe 25, or even 30 would be more realistic), but the idea is sound, which is to make people think about which lane they should be in and what should be expected about swimming in the fast lane, i.e. that if you're slow you're going to get overtaken a lot..... So don't get annoyed about it !

River Trent Bore in Gainsborough on 1st Sept 2019.
We missed the previous one in the morning as it was 50 min early, and this one was half a hour early too, but we made sure we got there earlier ! The dusk, partly illuminated by the path's streetlights, made it even more surreal, and its rushing sound was even more atmospheric in the quiet of the evening. Not sure if modern more "down focussed" LED street lamps would really light it up as well though, so take loads of powerful torches !