Bilbao's Iron Ring"Insurgent Advance Guard Breaks Through Bilbao's Iron Ring"
''

Ludington Daily News The ''Ludington Daily News'' is the daily newspaper of Ludington, Michigan Ludington ( ) is the largest city and county seat of Mason County in the U.S. state of Michigan. As of the 2010 census, the city population was 8,076. Ludington is a h ...

'', 14 June 1937. ( es, Cinturón de Hierro, eu, Bilboko Burdin Hesia), is a

fortification A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere' ...

around

Bilbao ) , motto = , image_map = , mapsize = 275 px , map_caption = Interactive map outlining Bilbao , pushpin_map = Spain Basque Country#Spain#Europe , pushpin_map_caption ...

in the Basque Country,

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

. It was constructed hurriedly by the

Basque Government The Basque Government ( eu, Eusko Jaurlaritza, es, Gobierno Vasco) is the governing body of the Basque Autonomous Community of Spain. The head of the Basque government is known as the ''Lehendakari''. The Lehendakari is appointed by the Basque P ...

during the

Spanish Civil War The Spanish Civil War ( es, Guerra Civil Española)) or The Revolution ( es, La Revolución, link=no) among Nationalists, the Fourth Carlist War ( es, Cuarta Guerra Carlista, link=no) among Carlists, and The Rebellion ( es, La Rebelión, link ...

to help defend the city from the

Nationalist Nationalism is an idea and movement that holds that the nation should be congruent with the state. As a movement, nationalism tends to promote the interests of a particular nation (as in a group of people), Smith, Anthony. ''Nationalism: Th ...

forces approaching as part of their

War in the North The War in the North was the campaign of the Spanish Civil War in which the Nationalist forces defeated and occupied the parts of northern Spain that had remained loyal to the Republican government. The campaign included several separate battl ...

campaign. The Iron Ring was a vast

labyrinthine In Greek mythology, the Labyrinth (, ) was an elaborate, confusing structure designed and built by the legendary artificer Daedalus for King Minos of Crete at Knossos. Its function was to hold the Minotaur, the monster eventually killed by t ...

fortification network around Bilbao, consisting of bunkers,

tunnels A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A Pipeline transport, pipeline is not a tunnel, though some recent tunnels have used ...

, and fortified trenches in several rings, protected by artillery. However, despite the extensive coverage, it was an antiquated defence concept similar to First World War fortifications, which made it vulnerable to modern warfare weapons of the time, such as aircraft and artillery. Additionally, the fortifications were designed to hold 70,000 troops but were eventually only held by 30,000, less than half conceived to defend it. In February 1937, the monarchist engineer that coordinated the works, Alejandro Goicoechea, crossed to the Nationalist side carrying plans and documentation. Therefore, the Iron Ring was easily overcome by Nationalist forces in the Battle of Bilbao when it was breached by an infantry assault supported by heavy air and artillery bombardment from 150 guns and 70 bombers, and the system was completely defeated within two days. Josu Chueca
«Burdin Gerrikoa puskatuta»
''36ko Gerra orain''. Imanol Villa

''El Correo'', 2007-02-11.

References

Fortifications of the Spanish Civil War Buildings and structures in Bilbao 1936 in Spain 1936 in military history {{SpanishCivilWar-stub