<br /> <p>Protesters set cars on fire with flares during the second day of the G20 Summit in Hamburg, Germany, on July 7. At the start of the summit a day earlier, police used water cannons in an effort to disperse demonstrators.</p><p>Heavy security was present from the outset, as police on Thursday warned protesters</a> their planned rally would not go ahead unless people removed face masks.</p><p>This video shows masked people breaking car and storefront windows and setting cars on fire with flares. Credit: Extinguisher TV via Storyful</p><br />
