I went and bought a new GoPro clip for my "non-GoPro but somewhat compatible" action cam, but unfortunately I didn't bring the necessary adapter and could only hook it up to one place on my backpack, where the only thing it could film in a normal riding position was the front wheel and the ground.
Kind of a scary video, speed feels worse looking down, and not being able to see where the bike is going in the video is a bit nerving.
Route: from Jätkäsaari to Meilahti, following the coastline.