Vast. Far bigger than where I am sure you come from; it varies so much along its landscape that it's difficult to summarize.
[ There's a tiny swell of pride in her voice; it's clear she thinks Britannia is a glorious place. But then doubt enters her voice. The child guide did mention, briefly, something about other worlds... could that be this at work? ]
How haven't you heard of Britannia?
[ 'A Number such as yourself should know Britannia well' is what she is thinking. ]