To us London is a hundred different places. It is never easy to know exactly what we mean when we use the word. Indeed, to the question ” What is London? ” there is no satisfactory answer, unless it be that it is the original little walled city that still exists. It contains St. Paul’s Cathedral, the Mansion House, the Guildhall, the Bank of England and London Bridge. Thousands of people work there in the day-time, but no one sleeps there at night but the Lord Mayor of London and a few hundred caretakers. Yet the physical boundaries of this ancient city are still visible. It is still possible to walk along the line of the Roman Wall that centuries ago limited the size of London to one square mile.

H. V. Morton (1892-1979), In Search of London