A BBC Witness History report recalls the emergency effort to rescue wildlife threatened by the creation of the Itaipu dam on the Paraná River between Brazil and Paraguay. The operation mattered because the dam’s reservoir flooded large areas of habitat, leaving thousands of animals at risk of drowning or being stranded.

Rescuers worked to capture and relocate animals as water levels rose, in what became a major conservation operation linked to one of the world’s largest hydroelectric projects. The article directs readers to a full BBC Sounds episode for the detailed account, but the supplied text does not give figures for the number of animals saved or the dates involved.