The Loire River is the longest river in France, and two of its cities are Nantes (6 letters) and Orleans (7 letters). Nantes is located in the western part of the country, on the Loire River's estuary, and is the sixth-largest city in France. It is known for its historical architecture, including the Château des ducs de Bretagne, a castle built in the 15th century. Orleans is located in the northern part of the country, about 130 kilometers south of Paris. It is known for its Gothic cathedral, the Cathedrale Sainte-Croix, which was built in the 12th century.