The carillon is a very public instrument; everybody can always hear what you are playing, so practising on it is not really possible. Thus, carillonneurs historically had a practice-keyboard that looks like the real keyboard of a tower instrument, but has tuned metal bars instead of bells. But for a study, it is, of course, necessary to play on real bells now and then. The city of Amersfoort has unique opportunities for this. The Carillon School is located in a historic building in the old centre of Amersfoort and has several study-keyboards. The Belgian Monument (Belgenmonument), with a small tower and an instrument, is located on the outskirts of Amersfoort. As it is not surrounded by houses, it can be played at any time. Last but not least, there is the the Tower of Our Lady (Onze-Lieve-Vrouwetoren) in the city centre, which houses two carillons – one from the 17th century and a modern instrument. These instruments are also in use by the school.