[notahacker]

Even in Athens I can imagine an ancient inhabitant being lost and confused amongst a grid of midrise concrete buildings. Then they'd turn a corner and catch a glimpse of the Acropolis...

London, sort of continuously inhabited since Roman times, wouldn't pass the test even if an ancient Roman inhabitant was standing on a street following the line of a Roman road and looking direct at the foundations of the London wall. Even the river course would be unfamiliar.