Old City Hall - 19th-century municipal building

Boston's Old City Hall at 45 School Street was constructed in 1862–1865 in the French Second Empire style and served as the seat of Boston municipal government from 1865 until 1969. After the city government moved to the new City Hall in Government Center, the building became one of the first major adaptive-reuse projects in the United States, housing private offices and restaurants. The structure's iron framing, mansard roof, and cast-iron detailing exemplify mid-19th-century municipal building techniques.