Manchester Town Hall, facing Albert Square in the heart of the city centre, was designed by Alfred Waterhouse and features a 280ft (85m) high clock tower.
Manchester City Council found the building needed a major overhaul to modernise its interior and refurbish stonework, windows and other features.
Work began in 2018 and has involved specialists skilled in stonemasonry, mosaic making, stained glass repair and manufacture, and horology.
Council photographer Barrie Leach recorded their efforts for the special exhibition.
