The Danube River — pictured here near near Budapest — begins in western Germany, flowing 1,770 miles onto the Black Sea. Among other countries, it passes through Austria, Hungary, Croatia, Serbia, Romania and Ukraine. It drains the territory of 19 countries, making it the “most international river in the world.” It features a richly diverse biological and ecosystem that has been rigorously abused by humans for the past 150 years. Due to dikes, dams and dredging, as much as 80 percent of the river’s wetlands have been destroyed. Organizations such as the World Wildlife Federation (WWF) are one of many working to restore and conserve the area.