Metz (French pronunciation: [mɛs]  ; German: [ˈmɛts]) is a city in the northeast of France located at the confluence of the Moselle and the Seille rivers. Metz is the capital of the Lorraine region and prefecture of the Moselle department. Located near the tripoint along the junction of France, Germany, and Luxembourg, Metz forms a central place of the European Greater Region and of the SaarLorLux Euroregion. So, Metz is a fellow member of the QuattroPole union of cities, along with Luxembourg City and German Saarbrücken and Trier. An important Gallo-Roman city, Merovingian capital of the Austrasia kingdom, birthplace of the Carolingian dynasty, cradle of the Gregorian chant, and one of the oldest republics of the common era in Europe, Metz has a rich 3,000 year history. The city has been steeped in Romance culture, but has been strongly influenced by Germanic culture due to its location and history. A basin of urban ecology, pioneered under the leadership of people like Jean-Marie Pelt, Metz gained its nickname, The Green City, boasting over 37 m (398 sq ft) of open ground per inhabitant and the city's historic downtown also displays one of the largest commercial, pedestrian areas in France. Metz possesses one of the largest urban-conservation area in France covering 162.9 ha (402.53 acres) and around 100 buildings of the city are classified on the monument historique list. Because its tremendous historical and cultural background, Metz benefits from its designation as a town of art and history. The city is home to some world-class venues such as the Arsenal concert hall, the Centre Pompidou-Metz museum, and the National Opera of Lorraine (along with Nancy). A historical Garrison town, Metz is the economic heart of the Lorraine region, being specialized in information technology and automotive industries. Metz is also a centre for applied research and development in the materials sector notably in metallurgy and metallography, the heritage of the Lorraine region's past in the iron and steel industry.