London, UK 8th September 2012 Teardrop shaped craft.I live on the top floor of a 3 storey block. As I sit at my computer I have a window directly to my left which gives me a view of a taller block (12 Storey), left of this block I get a good view of the horizon if I lean outside.At approximately 19:55 I glanced out of my window and saw a gun-metal black craft with 3 spike-like protrusions, one on top and a spike either side. There was no sound whatsoever from this object, I could hear the traffic and faint police sirens in the distance but no aircraft sounds. The craft's overall shape was a flattened Teardrop, with the curved portion at the rear. At first I thought it was a toy, I could clearly see the shape of the craft and exactly where the spikes meet the body. The craft appeared quite large in the sky, about 2cm if I was to pretend to hold it with my fingers. I used to be heavily into model aircraft and kites when I was growing up, I do have an interest in aviation and I'm not one to mistake everyday flying devices as something else.I quickly opened the window and leaned out. The craft travelled 8 o'clock direction towards the tall block directly ahead and disappeared behind the building. I watched intently for it to emerge from the other side, after about 1 minute I could see it again, but its position had changed. It was MUCH further away, whereas before it appeared fairly close, now it was just about visible above the horizon to the left of the building. The craft appeared to stop in the distance, turn around (from facing right, to facing left), then lower vertically beneath my line of sight.I waited for another few minutes after that to see if I could catch sight of it again, unfortunately that was the last of it. This has put me in a weird spot, I had no idea what to do with this. My mind literally cycled through everything I understood about things that fly the moment I laid eyes on it. It didn't fit, and that realisation actually startled me. I really needed to get this reported somewhere, thank you.