From the Smithsonian almost a year ago, here's the first part of it:
As Soviet forces advanced in Eastern Europe in 1944, Nazi troops began deliberately sinking their ships in the Danube River. For much of the past 80 years, the scuttled German vessels—including torpedo boats, tugboats, transport ferries and barges—remained hidden beneath the surface.
Earlier this month, however, some of the vessels reemerged from the water, per Reuters’ Krisztina Fenyo and Fedja Grulovic.
A summer drought caused the river’s water levels to drop, revealing the World War II wreckage near Prahovo, a river port town in Serbia. Some of the ships were almost completely buried under sand, while parts of others were more visible, including their command bridges, hulls, masts and turrets, according to Reuters.
The sunken vessels make it difficult for modern boats to navigate parts of the Danube, which travels 365 miles through Serbia. In Djerdap Gorge near Prahovo, the sunken ships have narrowed the waterway to roughly 330 feet.
Shipping by waterway is much less expensive than by trucks, so the countries in the area are motivated to remove the sunken ships and unexploded ordnance.