This huge trapezoid square is dominated by its Renaissance town hall, with its belfry and astronomical clock. This building, standing in the centre of the square, is surrounded by the three Caesar, Hercules and Arion fountains, as well as the monumental Holy Trinity column. The latter, 35m high, commemorates the end of a plague epidemic and was inaugurated in 1754 in the presence of the Empress Maria-Theresa. It is now a UNESCO World Heritage Site.