I was on a vacation in Australia and was staying at the Langham Hotel in Melbourne. My room was viewing the Yarra river, towards federation square. At around 8-9 PM, whilst looking out the window, appreciating an excellent view towards the city, I saw something strange hovering above the adjacent Quay West Hotel. There was a flat rectangular object that was very slowly moving towards the east. It had four dim white lights on each corner. Initially, I had a hard time trying to identify the object, thinking that maybe it was a plane. I saw no navigation or strobe lights, and there is no way a plane could fly so slow. As an aviation enthusiast, I knew most modern aircraft types, both military and civil, yet I am unable to associate this with anything I knew. Then I saw that there were 2 more similar looking objects of roughly equal size (about 50 m in length and 20 m in width) on the right and left of the first. The two other objects were hovering. Then the first object started to rotate (not turn or change direction) about 90 degrees and then dissapeared. This procedure was then followed by the craft on the left then the one on the right. That is all. I continue to be confused what happened, but i knew for certain that it was a craft of somesort.