Quebec City is one of the oldest European settlements in North America. French explorer Jacques Cartier built a fort at the site in 1535, where he stayed for the winter before going back to France in spring 1536. Quebec city was actually founded by Samuel de Champlain, a French explorer and diplomat on 3 July 1608, and at the site of a long abandoned St. Lawrence Iroquoian settlement called Stadacona. Quebec was the capital of New France and, after 1760, of the new British colony.
Quebec is the only North American city to have preserved its ramparts, together with the numerous bastions, gates and defensive works which still surround Old Québec. The Upper Town, built on the cliff, has remained the religious and administrative centre, with its churches, convents and other monuments like the Dauphine Redoubt, the Citadel and Château Frontenac. Together with the Lower Town and its ancient districts, it forms an urban ensemble which is one of the best examples of a fortified colonial city.
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The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.