The biggest demonstration began at 11:00 a.m. local time (09:00 GMT) on Deichtorplatz square in Hamburg. According to the latest police estimates, the event gathered almost 50,000 people.
The protesters' mood was largely positive, but the police, judging from the experience of recent violent protests, came fully prepared for potential violence outbreaks. A lot of policemen were deployed at the scene and the sky was patrolled by police helicopters.
Clashes erupted at about 15:00 local time, when members of far-left groups known as Black Bloc joined the protesters. The police managed to disperse the radicals but closer to the end of the protest the police reported about bottles thrown at officers. Several people were detained with some officers receiving injuries.
The two-day summit started in Hamburg on Friday. The forum brought together not only the leaders of the major world economies, but also thousands of demonstrators protesting against the international event and globalization among other issues. Several of the anti-G20 rallies in Hamburg have turned violent. According to the local police, over 200 officers have been injured in the clashes.