Ingolstadt is a city in Bavaria, Germany, on the banks of the River Danube, in the centre of Bavaria. In 2016, it had 133,638 citizens, making it the fifth largest city in Bavaria. It is part of the Munich Metropolitan Region. The Illuminati, an Age of Enlightenment secret society, was founded in Ingolstadt in the late 18th century. Ingolstadt is a setting in the novel Frankenstein by Mary Shelley, where the scientist Victor Frankenstein creates his monster. It is the site of the headquarters of the German automobile manufacturer Audi, defence aircraft manufacturer Airbus (formerly Cassidian Air Systems), and electronic stores Media Markt and Saturn.