This poster advertises an ecology seminar in Darłowo, Poland, organized by a regional environmental-education center. Ironically, it was held at a time when the country was primarily powered through the burning of lignite, the “dirtiest” coal. Since the 1980s, the border area shared by Poland, (East) Germany, and Czechoslovakia (now the Czech Republic) has been known as the Black Triangle, a region defined by its extremely high levels of pollution due to vast open strip lignite mines. As the most polluting of fossil fuels, burning lignite produces large amounts of soot, ash that contains toxic heavy metals that leach into the water table, and sulfur dioxide and nitrogen oxide that result in acid rain. While the energy generated from lignite was principally sold to foreign countries in order to obtain hard currency during the Cold War, Poland still generates as much as three-quarters of its domestic power from it today—by far the highest percentage in Europe. The country is currently the largest European consumer of coal. Under pressure from the European Union, Poland has committed to reducing electricity produced by coal to 37 percent by 2030, and 11 percent by 2040. By comparison, 20 percent of U.S. electricity and just 2 percent of that in the U.K. was powered by coal in 2022.