Of course this nighttime triangle could be something ordinary, but if so it isn’t displaying anything remotely like regulation lights, and over a large European city, that is hard to do these days without an immediate challenge from military aircraft–unless, of course, they already know that it isn’t a threat, and/or that there’s no point in challenging it.

Story Source:
http://www.youtube.com/watch?v=nWNO__M7p0Q