A Greek architect is proposing a giant U-shaped residential tower, called the designed for New York City could be the longest building in the world NOW WATCH: London is building Europe's tallest residential skyscraper. The largest dome diameters in Europe · The largest domes The tallest twin buildings in Europe · The tallest twin The longest building in Europe · The longest. Modlin fortress was sold at an auction in Poland. It is known for the longest building in Europe which is located on its territory. The winner was.