Balloons bombing Venice. 19th-century illustration of balloons being used to bomb the city of Venice on 22 August 1849. Venice, then part of the Austrian Empire, had declared independence in 1848. The city was besieged by Austrian forces. In this attack, the second of two balloon bombings, around 200 unmanned balloons, each six metres in diameter and on half-hour fuses were used. They were largely ineffective, though the Venetians surrendered two days later. Artwork from 'Aerostation - Aviation' (1911) by French civil engineer Max de Nansouty (1854-1913), part of the 'Les merveilles de la science' series of 1867-1891 by Louis Figuier.