No, this isn’t a literal giant ring of iron around Bilbao, but it is something almost as cool. The city of Bilbao has a long and storied history in the course of Spanish internal conflicts. This city has been besieged in the past 200 years not once, not twice, but three separate times. But why is that? The city of Bilbao lies in the northern Basque country. The Basque country just so happened to also be the heart of the Carlist Wars. These wars were a conflict over the Pragmatic Sanction of 1833, and the Fueros, traditional privileges that belonged to the Basque and Catalan privileges. The Carlists, the side in favor of the pretender Don Carlos, as well as the Fueros, had their support bases in the rural countryside of the Basque and Catalan territories. Bilbao, in fact, was the only major Basque city to side with the Isabellist government, and as a result was besieged twice during the Carlist wars.

But why are these prior sieges relevant to these clearly modern fortifications? In the Spanish Civil war, from 1936-1937, the city of Bilbao sided once again with the central government, now of the Spanish Republic. However, the Carlists once again rose up during the civil war, specifically from the Navarre region. The city of Bilbao was, for the third time, besieged by the very same rebels it fended off twice before, but now in a much more modern context. Gone were the days of line formations and pitched battles with lines of muskets, and here was the era of modern industrial warfare. 

The Iron Ring was a vast tunnel network built by the briefly independent Basque government when it seceded at the start of the Spanish Civil War, and was a vast, labyrinthine series of tunnels, trenches, and bunkers designed to defend the city. Yet, much like the French in the same period, the defenses were built to World War One specifications, and remained undermanned. Built for 70,000 men, it held 30,000, less than half that number. 

Worse still, they got a monarchist to design the fortifications for them, Alejandro Goicoechea, because clearly getting someone from the political group you’re opposed to to build the defenses you’re using against the very same group is a great plan. Almost needless to say, he defected to the Nationalists, the military insurrection against the Republic. Shortly after he defected, the city of Bilbao fell to the Carlist Requetes. It only took three tries and a decline into almost complete irrelevance, but the Carlists finally got the city.

The fortifications, or at least part of them, still stand today, and you can visit them just outside of Bilbao. Now, these defenses stand as a reminder of not just the siege they were built for, but the many sieges the city had to endure during the century of Spanish instability from the 1830s to the 1930s. They also stand as a reminder not to let Carlists make anti-Carlist fortifications. This series of fortifications can be used in a trip to discuss a variety of topics, from military strategy, to regionalism in multinational countries, and ideological disputes between regionalism and unitary governments, and conservative vs liberal concepts of nationhood.

Bibliography

Tromans, Nicholas. “J. F. Lewis’s Carlist War Subjects.” The Burlington Magazine 139, no. 1136 (1997): 760–65. http://www.jstor.org/stable/887780.

Parker, A. A. “Carlism in the Spanish Civil War.” Studies: An Irish Quarterly Review 26, no. 103 (1937): 383–98. http://www.jstor.org/stable/30097437.

Silva, Milton M. da. “Modernization and Ethnic Conflict: The Case of the Basques.” Comparative Politics 7, no. 2 (1975): 227–51. https://doi.org/10.2307/421550.

Heiberg, Marianne. “Insiders/Outsiders : Basque Nationalism.” European Journal of Sociology / Archives Européennes de Sociologie / Europäisches Archiv Für Soziologie 16, no. 2 (1975): 169–93. http://www.jstor.org/stable/23998600.

Woodworth, Paddy. The Basque Country : A Cultural History. Digital ed. [England]: Andrews UK, 2012.