Expo ’58 was held in Brussels from April to October 1958. Oddly enough, the theme was colonization given that it was the fiftieth anniversary of the establishment of the Congo Free State. The centerpiece of the Expo was the Atomium:
The really interesting bit, though, concerns Mozart. An autographed manuscript of Mozart’s Requiem was placed on display at the Expo. At some point, someone tore off the bottom corner of the manuscript – a scrap of paper containing the words “Quam olim d: C:”. If the beliefs around the manuscript are true, those words would be the last words that Mozart ever wrote.
To this day, the scrap has not been recovered.