The Anillo Periférico is the name given to the outer beltway of Mexico City

Mexico City

Mexico City is the Federal District , capital of Mexico and seat of the federal powers of the Mexican Union. It is a federal entity within Mexico which is not part of any one of the 31 Mexican states but belongs to the federation as a whole...

. The beltway gained major media attention when the Mexico City mayor, Andrés Manuel López Obrador

Andrés Manuel López Obrador

Andrés Manuel López Obrador , also known as AMLO or El Peje, is a Mexican politician who held the position of Head of Government of the Federal District from 2000 to 2005, before resigning in July 2005 to contend the 2006 presidential election, representing the unsuccessful Coalition for the Good...

, started a project to turn a southern section of the ring into a two-story highway. The second floor was finished in 2006.

The Periferico was originally planned by architect Carlos Contreras as early as 1925, together with other major roads such as the Viaducto Miguel Alemán

Viaducto Miguel Alemán

Viaducto Miguel Alemán is a crosscutting freeway, opened in September 1950, that runs east-west across the middle of Mexico City. In the center of the road is a river encased in cement to control flooding...

. Some parts of the beltway were built to follow the bed of a river; the flow of the river was modified to flow through a pipe.