1. La Trinca was very generous to the Besòs River when, taking advantage of the well-known waltz by Johann Strauss Jr., they wrote the lyrics for their song. The Blue DanubeIn 1975, he said that "the Besòs is green." And that was a gross understatement. Back then, it was one of the most polluted rivers in Europe. There was no life, practically no fish. Toxic foam was visible, and the stench was overwhelming for many days of the year. The lack of environmental regulations during the Franco regime and the scarcity of effective legislation meant that pollution went almost unpunished. Uncontrolled industrialization in the river basin, in the Vallès region and the Barcelona area, turned the river into a dumping ground with virtually no treatment. As a result, textile, chemical, and metallurgical companies contaminated the water with heavy metals and a whole host of toxic products. And it wasn't a crime. And there was no awareness of the damage being done to nature and the landscape. Furthermore, urban wastewater—in a time when towns and cities lacked treatment plants—turned some stretches of the Besòs into an open sewer. We can add that it was a river with a low natural flow, where pollutants became highly concentrated, and that aggressive urbanization along the riverbank gradually devoured the native vegetation. For all these reasons, the Besòs was the shame of Barcelona's northern border.