Walls constructed of human bones and skulls have been discovered beneath a Belgium cathedral.

The nine walls composed of bones and shattered human skulls were discovered by archaeologists while excavating the grounds of a Saint Bavo’s Cathedral in Ghent, Belgium, ahead of construction for a new visitor’s center at the cathedral.

Ruben Willaert of Restoration & Archeology/Decoration, the Dutch company that found the walls, told The Brussels Times that they were largely constructed from “stacked adult human thigh and shin bones” and that the intermediate zones were filled with “fragmented human skulls”.

A Controversial Cathedral With Skeletons In Its Closet

The human bone walls were discovered beneath the north side of the cathedral, formerly known as the Chapel of St. John the Baptist which was originally a small wooden construction consecrated in 942 AD by Transmarus, Bishop of Tournai and Noyon. A later Romanesque structure gave way to the construction of a Gothic church around 1274 AD and between the 14th through 16th centuries a new choir, radiating chapels, transepts expansions, a chapter house, nave aisles, and a tower were added to the religious super structure.