Before doing renovation or new construction in the 1600 year old town of Brno (officially settled in 1243 but occupied since the 400s), it is standard practice to do a preliminary archeological dig, but what they found under Jakubske namesti or "St. Jacob's Square" was a surprise to everybody.
Some 50,000 skeletons were stuffed under the square into a medieval charnel. Once piled in neat rows, at some point water and mud had flooded the gigantic underground ossuary and jumbled the thousands of bones.
The bones thought to be from the 1600 and 1700s, are believed to have been dug up from an old cemetery to make space for more burials, as in most of the ossuaries and catacombs in Europe. It is the sheer amount of skulls, bones and skeletons here, second only to the Catacombs in Paris, that make the Brno ossuary especially significant. It is clear that many of the people died of various disease which can be seen in the coloration of the bones themselves. Though all the bones are tinted yellow -- having never been exposed to sunlight -- the extra yellow ones likely died of cholera, while the red tinted bones probably died from the plague.
While the archeologists work on returning the crypt to its ordered pre-flood state, and the town of Brno gets ready to open its new found bone extravaganza to the public, much still remains to be done. Tunnels still filled with mud and bone lead directly to the St. James (mistakenly often called St. Jakob's) church where it is believed there are even more bones packed in the cellars underneath.
Unfortunately the bones are not yet open to the public. Due to having been exposed to water, the bones are still unsanitary and may carry bacteria and disease, and need to be cleaned before the ossuary can be fully opened to the public. The opening is planned for 2010-2011 but ask around and you may be able to get a small tour of the ossuary yourself.