Languages of the European Union which is understood by 51% of all adults, while German is the most widely used mother tongue, spoken by 18%. All 24 official languages of the EU are accepted as working languages, but in practice only two – English and French – are in wide general use and of these English is the more commonly used. French is an official language in all three of the cities that are political centres of the Union: Brussels (Belgium), Strasbourg (France) and Luxembourg City (Luxembourg). , the official languages of the European Union, as stipulated in the latest amendment of "Regulation No 1
European institutions in Strasbourg européen", "Droits de l'homme" and "Robertsau Boecklin" tram stations. The newest Council of Europe buildings were inaugurated in 2006 and 2008, and the newest European Union building was inaugurated in 2017. In all, there are fourteen different buildings in the European Quarter: seven belonging to the Council of Europe, five belonging to the European Union, plus Arte and the IIHR. The first European institution to be based in the city was the Central Commission for Navigation on the Rhine. Set up in 1815 by the Congress of Vienna, it is the oldest international organisation in the world but has only