Medieval Underground Tunnel Discovered Inside a 6,000-Year-Old Neolithic Burial Site in Germany

A remarkable archaeological discovery in central Germany has revealed a rare medieval underground tunnel hidden within a much older Neolithic burial complex, shedding new light on how ancient landscapes were reused across millennia.

During archaeological excavations near the village of Reinstedt in Saxony-Anhalt, researchers uncovered a late medieval “Erdstall”—a man-made underground passage system—cut directly into a Neolithic trapezoidal ditch dating back to the 4th millennium BCE. The discovery was made by the State Office for Heritage Management and Archaeology of Saxony-Anhalt during investigations ahead of a planned wind energy project.

A Site Used for Over 4,000 Years

The excavation area, located on a low hill known as the Dornberg east of Reinstedt, had already proven archaeologically rich. Findings include a Neolithic trapezoidal ditch from the Baalberg culture, poorly preserved burial remains from the late Neolithic period, and traces of a possible Bronze Age burial mound. Together, these discoveries demonstrate that the site was repeatedly used for ritual and funerary purposes over thousands of years.

What makes the new find extraordinary is the discovery of a medieval underground structure cut directly into this much older Neolithic feature. This type of structure, known as an Erdstall, consists of narrow tunnels carved by hand into compact soil, often loess. Such features are rare in northern Germany and have long puzzled archaeologists.

What Is an Erdstall?

Erdställe (plural) are artificial underground passage systems typically dating to the late Middle Ages. Their purpose remains debated. Some scholars interpret them as hiding places during times of conflict, while others suggest they may have served ritual or symbolic functions.

In Reinstedt, archaeologists initially mistook the feature for a grave due to its elongated shape and the presence of a large stone slab. However, as excavation continued, the pit extended deeper and revealed sloping fill layers, medieval pottery fragments, stones, and preserved voids—clear indicators of an underground tunnel system.

Inside the Medieval Tunnel

The tunnel, which curves toward the northwest, measures approximately one to 1.25 meters in height and between 50 and 70 centimeters in width. Parts of the passage are covered with a pointed gable-shaped ceiling, and the entrance area includes a carved step and a niche in the wall.

Among the most intriguing finds inside the tunnel were a horseshoe, fragments of late medieval ceramic vessels, a fox skeleton, and numerous small mammal bones. At the lowest level, archaeologists uncovered a thin charcoal layer. Because there was no reddening of the surrounding soil—only slight hardening—the team believes the fire burned briefly rather than continuously.

A cluster of large stones stacked at the narrowest part of the entrance suggests that the tunnel may have been deliberately sealed, possibly after its final use.

Why Build a Tunnel in a Prehistoric Grave Site?

One of the most compelling questions raised by the discovery is why a medieval community chose to dig an underground tunnel inside a visible Neolithic burial monument.

Archaeologists propose two main explanations. First, the ancient ditch system may still have been recognizable above ground in the Middle Ages, making it an ideal landmark for relocating a hidden refuge. Alternatively, the site’s association with pagan burials may have caused it to be avoided by the general population—making it a perfect, undisturbed hiding place during uncertain times.

A Rare Window Into Layered History

This discovery highlights how landscapes can accumulate meaning and function over thousands of years. The Reinstedt Erdstall is not only a rare medieval structure but also a striking example of how later societies interacted with, reused, and reinterpreted prehistoric monuments.

As renewable energy development continues across Europe, such discoveries underscore the importance of archaeological surveys in preserving cultural heritage before construction begins.

Further analysis of the site is ongoing, and the findings contribute valuable new data to the study of medieval underground architecture and long-term land use in Central Europe.

Landesamts für Denkmalpflege und Archäologie (LDA) Sachsen-Anhalt

Cover Image Credit: Aerial view of the Middle Neolithic trapezoidal ditch; the disturbance caused by the late medieval Erdstall is visible in the southeastern section. Simon Meier – State Office for Heritage Management and Archaeology of Saxony-Anhalt