It was closed night, just after having dinner and talking all with each other in the roof of the building where there was a big terrace.Then a mate and me watch the ufo lightned just by the city lights, it did not glow or have any visible light but it reflected the lights of the city, it just appeared flying so low the city lights made us able to see it, its shape was strange because it was so "small" to have anyone inside it, now I think it could be a drone, it was a thin cylinder rememebered me the city tube street lights but bigger, long as a city bus maybe or a truck, and a lot of spheres from the start to the end of it symetricaly situated.we could not hear anything apart from the city noises, it flied real low and close to us as it passed away we stop being able to see it as there were other buildings around. It flew in a perfect straight line and at slow maintained speed.maybe someone has seen things like this. it was some years ago but i remembered very well the shape and the way it flyed so steady and silently.best regards.