The delta of the Danube River, Europe's best preserved river delta, can be seen in this image taken by the European Space Agency's (ESA) Envisat satellite earlier this year.
The Danube originates in the Black Forest in Germany as the smaller Brigach and Breg rivers, which converge to form the mighty Danube. Flowing southwest for more than 1,740 miles (2,800 kilometers), it finally pours into the Black Sea via the delta.
Designated a World Natural Heritage Site in 1991, the Danube Delta is a labyrinth of river channels, lakes, bays, floodplains, marsh and reed beds. This vast triangular delta is home to an extremely rich variety of birds, fish, animals and plants.
The delta protrudes into the Black Sea owing to the continual deposition of alluvial material and is continuing to grow seawards at a rate of up to 100 feet (30 meters) per year, according to an ESA statement.
The natural reserve lies largely in Romania, which is set to be ESA's newest Member State.