A $25 billion dam-building plan for Spain's Ebro River would submerge entire towns, displace tens of thousands of rice and fish farmers, and poison the wetlands of the river delta with salt. Luckily, Pedro Arrojo-Agudo, an economics professor at the University of Zaragoza in Spain, has stepped off campus to organize an enormous grassroots movement against the plan. Thanks to his efforts, hundreds of thousands of people have gathered across Spain to protest the project. On April 14, Arrojo-Agudo was awarded one of six 2003 Goldman Environmental Prizes for his work to stop the dam-building. Read an interview with him as part of Michelle Nijhuis's special six-part series on the Goldman Prize winners, only on the Grist Magazine website.