The Roman Monuments, Cathedral of St. Peter and Church of Our Lady in Trier are buildings and monuments of particular historical importance in Trier, Germany, that were together listed as a UNESCO World Heritage Site in 1986. These sites demonstrate the political, economic, and historical importance of Trier during the Roman Empire as one of the four capital during the Tetrarchy period, and as a prominent city during the early days of the Holy Roman Empire in the Middle Ages. From UNESCO/CLT/WHC: In 2009, the site was featured on a golden 100-Euro coin.