The exhibition was open to the public from 12 May 2017 to 31 December 2017.
On the occasion of the 150th anniversary of the Treaty of London, signed on 11 May 1867 by Prussia, the French Empire, the Russian Empire, the United Kingdom, the Kingdom of Belgium, the Kingdom of the Netherlands, the Austro-Hungarian Empire and the Kingdom of Italy, the Musée Dräi Eechelen, in collaboration with the National Archives, organised an exhibition entitled '1867. Luxembourg – ville ouverte'.
It displayed the Final Act of the Treaty for the first time, as well as the 8 ratifications by the signatory powers with the minutes. Alongside other previously unseen documents and objects, the exhibition illustrated how the dismantling of the Fortress, stipulated by Article V of the Treaty, transformed Luxembourg into an open city, as later officially declared by Grand-Ducal Royal Decree of 22 May 1883.
