This is neat. Some things I like about finland/helsinki: Happy down to earth citizens, socially liberal with far less echochamber/signalling/two-faced bs than california for instance, tons of Finnish sauna, & great air quality for a big city.
Helsinki is 600,000 people and 400/km^2. That's essentially the same as Oklahoma City. I know OKC has a basketball team and city is in the name, but most people wouldn't call OKC a big city and wouldn't be surprised by better air quality compared to places with millions of people.
For cities, as so many other things, it's not all about size.