The M-40, in Spanish transport, is a Madrid orbital motorway. It is the second-outermost of the Madrid orbital highways, the M-30 being the closest to the centre of Madrid. It surrounds 17 out of the 21 districts of Madrid and the contiguous town of Pozuelo de Alarcón. In terms of length and surface surrounded, it may be compared to London's North and South circular roads, or Paris' A86 super-périphérique. From Wikipedia
