The Granary (horrea) at Housesteads Roman Fort (Vercovicium) on Hadrian's Wall near Bardon Mill, Northumberland.
The granary was positioned high up the hillside within the fort and was on a raised floor (supported by these pillars) to keep the grain and meat out of reach of damp and vermin. There would probably have been vents in the outer walls to promote air circulation within this food store.
Housesteads is the best surviving example of a Roman fort in Britain, and one of the best-known forts from the whole Roman Empire.