As far as I could remember, the event happened between 1981-1982. I was seating alone late at night in the fountain square right in the city center. Then I heard a noise like helicopter roaring coming from the north and a huge object passed slowly before my eyes at about 1000ft over the top of buildings. As it was not too dark, I could see that it was a huge and dark object emitting lights all over the surface. At first, I was thinking why there was an helicopter flying low so late at night and I nearly shouted out loud but I could not because there was a curfew imposed by the government authorities at the time. The object did not chane its path and disapeared south.I did not run after to follow its course.