Johannesburg City Hall built in 1915 is a rare example of well-preserved colonial architecture. Designed in grand Edwardian style it houses an immensely impressive organ. Now a national monument, the building took over a part of the city that was previously Market Square, and the space in front of the City Hall over a number of years was a gathering place for civil and political protests. Worth a pop in if you are in the area. Entrance on President Street.