Travel along the coast up north of Barcelona, and you’ll notice three absolutely massive towers standing alone in vast stretches of empty fields. They’re the Tres Xemeneies (Three Chimneys), and they have a long, complicated past that led to them being abandoned and almost torn down.

These roughly 650-foot-tall chimneys were constructed in the 1970s as part of a thermal power station. Even before it opened, the industrial structure was plagued by controversy.

Locals objected to the station’s construction, disliking its appearance as much as the environmental implications. When workers building the station in 1973 went on strike in a bid for better working conditions, the police responded with lethal force, killing one of the workers. Decades later, the company managing the site would go to court over accusations of black rain and pollution.

The plant shut down in 2011, and the company that owned it wanted to tear it down and get rid of the structure that had caused so many issues. But oddly enough, the locals had grown attached to it. Sure, the chimneys aren’t the most aesthetically pleasing fixtures, but they are the most dominating part of the skyline for miles around. A local coalition even formed in a bid to save the towers as a monument to the workers who built it. And in a spur of charity, the company gave the property to the local government in 2015 after years of lawsuits and tension.

Now, these chimneys are a monument to the people who built them; a symbol of something unwanted but summarily accepted and treasured for its complicated past. The local council hopes to one day use the site for homes and retail, or perhaps a museum.

For now though, the chimneys exist only to marvel at from a distance. You can’t enter the property to see them, as a large, possibly electrified fence wraps around it. Looking up at these imposing feats of engineering, it’s no wonder why locals refer to them as “la Sagrada Familia de los obreros,” or “the Sagrada Familia of the workmen.”