Simplify the following text for a Grade 8 native English-speaking person.
Original: The GLA is different from the Corporation of the City of London with its largely ceremonial Lord Mayors , which controls only the square mile of the City , London 's chief financial center .
Simplified: The GLA is different from the Corporation of the City of London with its largely ceremonial Lord Mayor . Corporation controls only the square mile of the City , London 's chief financial center .