[dcminter]

The City of London, aka "The City", aka "The Square Mile" is not the same thing as Greater London or even what's usually called "Central London." I don't think "Central London" has an agreed exact definition, but it's likely what you thought the parent post meant.

The City is a specific area, more or less covering the same area as the original Roman city. It's the original financial district - though a lot of that moved to Docklands at the tail end of the 1900s.

It's much more built up than even adjacent Westminster ("The City of Westminster") and definitely has far fewer trees.