Five Roman iron nails, late 1st century AD.

UNITED KINGDOM - MAY 23: Five nails from the Roman Legionary fortress at Inchtuthill, near Dunkeld, Perthshire, Scotland. The Roman camp at Inchtuthill was constructed by Agricola in c 84 AD. During recent excavations, a hoard of over 875,000 iron nails was found at the unfinished Legionary fort. Upon abandoning the fort, the Romans secretly buried this store of valuable heavy iron nails in a pit. This was to prevent their discovery by the Caledonians, who could potentially have used the iron to make into weapons. The nails would have been made by the legion's blacksmith and larger examples were used to hold the wooden stockade around the fort in place. (Photo by SSPL/Getty Images)