About 5 years ago I was at home in Aarhus, expecting a visit from a friend. There's a buzz at the intercom, and I go out to let him in. But I can hear he's not opening the door downstairs, so I stick my head out of the window to see what's up.
My friend is standing downstairs alright, and I ask him why he doesn't come in. He just pointed up and said:
Look at that.
And there above the houses this big metal tube was silently floating across the street. It was actually flying this low, about 75' over the roof.
It was there for a few minutes, it just floated across the street and disappeared behind the house you see in the picture.