In 1900, the Métropolitan subway (Métro) in Paris opened the first eight stations on its first line running east-west through the centre of the city from Porte de Vincennes to Porte Maillot. Within two months the total number of stations became 18, as more were opened on 6 Aug and 1 Sep1900. Fulgence Bienvenüe was the engineer in charge of construction. The line was built close to the surface using the "cut and cover" method along existing streets. Its Art Nouveau entrances were designed by architect Hector Guimard.With extensions built in the 1930's and 1992, it now extends from La Défense high-rise district in the west to the Château de Vincennes, a medieval castle in the east. Still known as line number 1, it is the busiest route.«