Stadin silakkamarkkinat or Helsinki Baltic Herring Market if you want to use English name is annual Fish market at the beginning of October. It is week long event which was held first time 1743.
You might see some continuity errors here because some of the footage was shot 2016 and some was shot 2017.
Both year's footage was shot during week day's evening. It doesn't show how popular event was during weekends or during daytime. It was easier to move with camera when there were less people around.