Such highly finished drawings by Hackert, younger brother of Jakob Philipp Hackert (whose Waterfall of Marmore at Terni is nearby), are extremely rare. The Hackert brothers were among the first Romantic artists to adopt the practice of drawing and painting en plein air in Rome. Italians were amazed when they saw the artists roaming the countryside with large portfolios, executing finished outline drawings entirely from nature. This drawing accurately represents an aqueduct built in the middle of the 18th century in southern Italy. The degree of finish, meticulous detail of the vegetation and rocks in the foreground, recession of space, and subtle treatment of light are astonishing.