Mannheim is the commercial and cultural centre of the European metropolitan region known as the "Rhine-Neckar triangle". The town has maintained its reputation within art and music circles to this day. With the city centre and the most attractive residential areas lying on the two rivers, the Rhine and Neckar, the area boasts many green oases. The agglomeration of Mannheim/Ludwigshafen enjoys perfect transport links. The parallel streets of the two main axes are essentially nameless, instead the squares lying between them bear designations consisting of a combination of letter and number. This retained naming system is unique throughout architectural history. Additionally desirable is Mannheim’s close proximity to the Rhine Main region and to historic Heidelberg.