[shadowlands1960]

The Romans would build immense fortifications as a form of intimidation, probably the case here.

[Harmless Teddy Bear]

The Romans did not build it.

[SunkenCiv]

Future emperor Vespasian rolled across Britain with Roman artillery (the various catapault doodads) and reduced places including Maiden Castle each in a matter of days. The Celtic tribes in his path had never seen anything like it, and the futility of resettling those spaces was obvious. Also obvious is that they really were built for security, not as symbols, ritual spaces, or (just) cattle pens.