I was sitting at my computer working when I heard the bang. It was quite loud and it literally shook the whole house. I felt my chair move. I didn't know what the hell it was and I though it was an explosion at a construction site very near when I realized there was no such site that near.
There was nothing on the situation room web page:
http://www.tilannehuone.fi/halytys.php
A few moments later I read in the online version of the local newspaper that it was a fighter jet on a supersonic flight over our city.