Ghost stations of the Paris Metro
Ghost stations of the Paris Metro are stations that have been closed to the public (or never opened) and are not used in commercial service. For historical, geographical or economical reasons, many stations on the Paris Metro have been closed or never opened, made inaccessible and lie unused, conferring a sense of mystery over Parisians and sparking interest of the Urban explorers.
Source: Wikipedia — Ghost stations of the Paris Metro (CC BY-SA 4.0)