The M-30 orbital motorway circles the central districts of Madrid, the capital city of Spain. It is the innermost ring road of the Spanish city, with a length of 32.5 km. Outer rings are named M-40, M-45 and M-50. Its length and the surface surrounded by the M-30 is comparable to the Boulevard Périphérique of Paris, the Grande Raccordo Anulare of Rome or the London Inner Ring Road.