The Drava River originates in the shadow of the Dolomites in the eastern Alps and flows for 750 kilometres before joining the Danube in Croatia's Kopački Rit Nature Park, near the city of Osijek. The fourth-largest Danube tributary flows through five different countries, making it one of the most significant east-west axes in Europe.

Like most great rivers, the Drava begins as a series of small streams. Fire salamanders, white-throated dippers and European graylings live in or alongside these currents. The breeding season of the white-throated dippers begins early in the year, when the otherwise sedate streams often become rushing torrents of water. The small songbirds construct their nests with great care and attention, meticulously selecting every leaf, twig or piece of moss used to line the nest to ensure that the chicks can grow up safely. The birds also hunt for insects and small aquatic animals among the stones on the riverbed, ready to dive headfirst into the stream if a tasty morsel catches their eye. Despite their swimming and diving skills, the birds must be careful: the combination of meltwater and torrential rains can quickly turn the small streams into raging currents that endanger the nests and the eggs or chicks within.

Fire salamanders prefer to make their homes in the surrounding forests, but females will come down to the water to lay their larvae in the stream. The larvae emerge almost fully formed in a thin sac they cast off as soon as they are deposited in the water. The stream then serves as a nursery as they mature. Grayling reproduction is a busier affair: during breeding season, the fish travel upstream to their regular spawning grounds. Once they arrive, the males have to compete for the attentions of the females before they can finally reproduce.

These days, wild stretches of the Drava are few and far between. The river has been tamed by humans and channelled through concrete over long distances. Finally, once it reaches the border between Hungary and Croatia, the river is able to return to a more natural course and shape the surrounding landscape, creating sand and gravel banks, branches and wetlands. These varied habitats are home to innumerable bird species including sand martins, little terns and white-tailed eagles. Eventually, the great river merges with the Danube to shape Europe's Amazon.

The Hungarian nature documentary makers Szabolcs Mosonyi and Erika Bagladi spent three years capturing the stunning variety of the natural world in and around this river environment, from the springs and streams at its origin to the regulated stretches at the centre and the spectacular wetlands at the confluence of the Drava and Danube rivers.