The construction of a new administrative building in Nieuwpoort, Belgium, took an unexpected and humourous turn as archaeologists found a cache of 500 medieval cannonballs. The high-quality finish led archaeologists to believe they were intended for firearms. 

The cannonballs varied in size, suggesting that Nieuwpoort had a diverse arsenal. A cannon is even depicted on a map drawn by Antonius Sanderus in 1641, close to the excavation site. The artifacts that primarily made of natural stone are dated to between 1350 and 1600 AD.