Line 6 is probably one of the network's most interesting lines. Much of it is overground, and there is a lot that can be seen from its imposing viaducts. Line 6 was envisaged to be a circular line along with Line 2 - which is why they start and end at the same stations. It was in fact originally called Line 2 Sud. Line 6 also uses rubber-tyred MP73 stock, which gives improved grip and noise reduction on the open-air section.