Fort de la Chartreuse was built between 1817 and 1823 to defend the city of Liege. Has been abandoned since the fortification by the military in 1891. The following years Germans used it as a prison between 1914 and 1918 and Americans as a military hospital between 1944 to 1945. The Belgian army left the site in 1988. Even if in complete decay it can still remind of its historical past!