Dozens of Nazi-Era Ships Are Emerging in the Danube. How Did They Get There?

Some ghosts haunt. Others warn. The twenty-odd German World War II shipwrecks that have once again surfaced from Europe's drought-stricken Danube River this summer do both.

They were part of a convoy of some 200 vessels Nazi Germany scuttled near the Serbian port of Prahovo in September 1944. To prevent the Soviets from advancing, they were sunk across Prahovo’s shipping channel. Eighty years on, the wrecks, still holding live ordnance, continue to obstruct boat traffic. The water is now so low that one ship lies almost entirely on dry land, beached in sand.

Not just a haunting symbol of the past, the ships’ visibility is an ominous warning of our environmental future.

A punishing heat wave has left much of Europe in drought. With rivers running at record-low levels, the economic consequences have been severe. Unable to bear their usual weight, barges must sail half-loaded, driving up the cost of everything that moves by water. Power plants have been pushed to the brink of shutdown, and governments across Central and Eastern Europe have had to conserve electricity.

Compounding the problem is that the heat is not landing on healthy rivers. In their natural state, Europe's rivers once spread into side channels and stored water across the land around them. But two centuries of damming and dredging for power and navigation have stripped much of that capacity away.

"European rivers are already sick," says Ulrich Eichelmann, a conservationist who leads the Vienna-based Riverwatch.  “This heat wave makes the damage more visible.”

Why Dozens of Ships Sank to the Bottom of the Danube

The Danube is Europe's second-longest river, running through ten countries before emptying into the Black Sea. Where the wrecks lie, along a stretch that forms Serbia's border with Romania, the river has been a strategic crossing since the time of the Romans, who built a fortified river port there called Aquae.

For most of World War II, the Danube acted as Germany's lifeline in southeastern Europe, carrying raw materials and war supplies upstream on a commercial fleet it had seized from occupied countries. That ended in August 1944, when Romania—until then a German ally—was overrun by the Soviets and switched sides, turning the river's left bank hostile for hundreds of miles.

In response, Berlin immediately ordered its Black Sea Fleet and Danube flotilla upstream. What assembled was less a war fleet than an evacuation: more than 4,000 people aboard barges, landing craft, a hospital ship, and tugboats converted into minesweepers. But the Iron Gates gorge upstream, the convoy's only way out, was already in Soviet hands. Four attempts to break through failed, and on the night of September 6, 1944 the crews began sinking their own ships at Prahovo.

"The remains of the scuttled German fleet serve as a kind of war memorial, preserving the memory of an event that, as far as I am aware, has no parallel from the World War II era," says Gordana Karović, a curator at Belgrade's Museum of Science and Technology who wrote the definitive account of the sunken fleet.

Reemerging From the River

The wrecks first broke the river’s surface in 2003. In 2011, another year of low water on the Danube, Karović dove underwater and filmed several hulls. The wrecks reappeared in 2022, and again in 2024. But nothing in the record matches this summer, when the river has fallen so far that hulls, only briefly glimpsed before, now stand clear of the water. "The situation is extraordinary," says Karović.

Getting them out has proved far harder than finding them. In the years after the war, nine vessels were raised, but the rest have stayed. As water levels recede, the wrecks narrow the navigable channel commercial vessels can pass through, causing a bottleneck. A few years ago, Serbia launched a roughly $30 million operation to remove 21 wrecks, funded by the European Investment Bank, which estimates the blockage costs the country almost $6 million a year in economic losses. One minesweeper has been lifted.

It's not just money. What is still inside the hulls has also made the work slow and dangerous.

"This operation is exceptionally demanding because the quantity and layout of explosives within the wrecks remain unknown, representing a constant hazard that must be seriously factored into all planning," Karović says.

Europe’s Hotter, Thirstier Air

The drought has been straining rivers across the continent, with consequences running from diminishing drinking water supplies to threats to nuclear plants, which need large volumes of river water to cool their reactors. In Hungary, the Paks nuclear plant, which supplies nearly half the country's electricity, had to be powered down for the first time in its 44-year history.

In Romania, where Danube flow fell to roughly a third of its normal August average, the army resorted to blasting rock from the riverbed to steer water toward a nuclear plant's cooling intake. When that wasn't enough, authorities sank four rock-filled barges to build a barrier diverting more water toward the plant.

Scientists say climate change is driving the drought, but not in the way most people assume. Across eastern Europe, rainfall shows no clear long-term decline. What has changed is the air itself.

"Temperatures are increasing strongly over Europe, and the atmosphere is consequently getting thirstier," says Sarah Kew, a climate scientist at the Royal Netherlands Meteorological Institute and lead author of a World Weather Attribution study published last month.

Warmer air evaporates more water from soil and vegetation, so a rainfall shortage that once would have passed without consequence now produces drought.

"Drought conditions can be reached more rapidly for the same rainfall deficit," Kew says. In eastern Europe, a soil moisture deficit as severe as this year's has become roughly eleven times likelier as a result of human-caused climate change.

Rivers are the last link in that chain. A river is fed less by rain falling directly on it than by water draining off the land around it. When the soil is parched, it absorbs what rain does fall rather than releasing it downhill. Dry ground upstream means a thinner river weeks later.

One Solution—Restoring the River’s Natural Ecology

Record low water levels on the Danube are exacerbated by how Europe has engineered its rivers.

The continent's waterways are the most dammed on earth, and two centuries of straightening, dredging, and diking have stripped away the floodplains and wetlands that once absorbed water and released it slowly.

Along the Danube, roughly 80 percent of the original floodplain is gone. A channelized river runs faster, warms quicker, and holds nothing in reserve for when the rain stops.

And yet the response, as the Romanian blasting shows, has often been more engineering, which ecologists and climate scientists alike say is the wrong approach. "What we need to do is to restore the rivers, give them more space, because natural river systems are natural cooling systems," says Eichelmann, the Riverwatch conservationist. Undoing drainage, reopening side channels, and letting the land hold water like a sponge rather than a ditch are all part of what that would mean in practice.

He also adds a warning.

While a big river like the Danube commands attention both because of its economic importance and for throwing up spectacular revelations like the shipwrecks, smaller rivers are also deteriorating. Eichelmann notes that "The damage on smaller rivers is often much more severe.”