At first glance, Denmark’s Bay of Aarhus looks like any other stretch of sea. However, beneath its calm, dark waters lie Stone Age settlements that were drowned by the sea more than 8,500 years ago. Now, archaeologists are diving deep to study this hidden world, hoping to learn how early humans lived as rising waters from Ice Age melt swallowed the coast. 

This underwater search is part of a six-year international project worth €13.2 million ($15.5 million), funded by the European Union. Researchers from Europe’s various museums and universities are working together to map parts of the Baltic and North Seas. 

The timing of this project is critical because archaeologists fear that as Europe rapidly expands offshore wind farms and other sea-based infrastructure, these ancient landscapes could be lost forever unless scientists study them now.

Searching for time capsules underwater

In the Bay of Aarhus, divers descended around 8 meters (26 feet) below the surface to explore what was once a Stone Age shoreline. Unlike many finds that are located inland from the ancient coast, this settlement was built directly at the water’s edge. That makes it especially valuable for studying how early hunter-gatherers lived by the sea.

The team carefully excavated about 40 square meters (430 square feet) of seabed using a special underwater vacuum that gently collects sediment and artifacts. Even though the site is small, the finds have been remarkable. The researchers found animal bones, stone tools, arrowheads, a seal tooth, and a small piece of worked wood, possibly a simple tool. 

The waterlogged environment, low in oxygen, has preserved materials that would normally decay. For instance, even delicate items like hazelnuts and wooden fragments remain intact.

“It’s like a time capsule. When the sea level rose, everything was preserved in an oxygen-free environment … time just stops. We find completely well-preserved wood. We find hazelnut. … Everything is well preserved,” Peter Moe Astrup, one of the researchers and an underwater archaeologist, said.

To build a timeline of when the seas overtook these lands, the researchers are also using dendrochronology, the study of tree rings. Submerged tree stumps trapped in mud and sediment can be dated precisely. 

This allows researchers to know almost the exact year when coastal forests drowned as the sea rose (an event that unfolded about 8,500 years ago) by roughly two meters (6.5 feet) per century during the Stone Age. Such detail is crucial for piecing together how quickly the environment shifted and how humans may have responded.

Interestingly, the Aarhus site is just one of several locations under investigation. Excavations off the German coast have also begun, and future dives are planned for two much harsher sites in the North Sea. That area once contained Doggerland, a vast plain that connected Britain to continental Europe before it disappeared under the waves thousands of years ago.

Why do these findings matter today?

These underwater excavations are not just about satisfying curiosity about the past. They offer a direct window into how human societies coped with rapid environmental change. Around 8,500 years ago, people had no choice but to adapt as rising seas reshaped their world. 

Today, global sea levels are once again on the rise, about 4.3 centimeters (1.7 inches) in just the past decade, largely due to climate change. By studying how Stone Age communities responded, researchers hope to gain insights that could inspire resilience strategies for modern societies facing similar threats.

Next, the researchers plan to continue their dives in more difficult North Sea locations and expand the analysis of the materials already recovered. 

Large stretches of the seabed remain unexplored, and many ancient sites may have been destroyed by tides or construction. This makes every fragment of bone, wood, or shell a vital clue in piecing together the story of early human life along Europe’s coasts.