Despite such a proud history, Belgrade fortress is beginning to crumble from the effects of a combination of coal smoke and fertilizer from the flower beds of the surrounding park.
The website medievalists.net reports that a Serbian and French team have been analyzing a black crust that’s been forming on the limestone walls and found it to contain syngenite, a double sulfate of potassium and calcium that’s the result of the use of potassium fertilizer in the flowerbeds along some parts of the walls.
Pollution from cars and coal-burning factories has long been known to chip away at stone. A similar black crust can be seen on many of the historic walls in Oxford. This new study shows that caretakers of historic sites have to be careful how they beautify the grounds.
Belgrade fortress is treat for any history buff or castle fan. Located at the strategically important confluence of the Danube and Sava rivers, a fort was first built here by the Romans in the first century AD. This was one of the rougher regions of the Roman Empire and the fort saw action numerous times before finally being destroyed in the early 7th century by the Avars and Slavs. Legend has it that Attila the Hun is buried somewhere in the grounds of the castle.
The Byzantine Empire, as the eastern remnant of the Roman Empire came to be called, continued to value the site and built a massive fort there in the 6th and again in the 12th century. Belgrade fortress was later the pride of the emerging Serbian nation and was improved and expanded several times. When Austria ruled the area in the 18th century it saw action against the expanding Ottoman Empire.
The extensive grounds are very popular with locals and include a park, a military museum, and a zoo.
Photo by CrniBombarder!!! (from Wikimedia Commons)