The historic center of Graz is considered one of the best-preserved city centers in Central Europe, and in 1999 UNESCO included it in the list of world cultural heritage. It is characterized by a mix of houses from different periods and different architectural styles. The old town center is made up of more than 100 buildings, with styles ranging from Gothic to Modernism. The latter was also used by HoG Architektur (Hope of Glory) in the construction of one of the "stumps" where the residential building was built. Instead of the classic facade, the Ballhausgasse building was given mirrors that reflect the nearby building, successfully masking the true appearance. buildings.