Germany's second largest city, Hamburg, will host the G20 this week. With 6,000 delegates and 3,000 members of the global media flocking to the city, residents and the police are bracing themselves. Adding to the problems created by the somewhat baffling choice of a city center location, Hamburg is home to a burgeoning left wing scene, far from shy to take to the streets.Indeed, a number of protests are planned to coincide with the G20, the largest of which is expected to involve up to 100,000 people. Thursday's Welcome to Hell march will also provide a challenge for the police and security services, when around 8,000 leftwing radicals and anarchists are expected to descend on the location of the summit - the Congress Center.Complicating the security operation further, the Congress Center is located on the edge of the 'Schanzenviertel', an area of the city much-loved and lived in by those involved with or sympathetic to left wing groups. According to the Hamburg police force , there are 1,090 known left wing extremists residing in the city, 620 of which are considered to be prone to violence. Looking to the whole of Germany, the figures grow to 26,700 and 7,700 respectively.The resources required to police this potentially huge group of people leaves less available for the ever-present threat of jihadist terrorism . In addition to the far-left and far-right, there are believed to be at least 640 Salafists living in Hamburg. 310 of these have been classified as jihadist. In the worst case, this could all end up leading to a perfect storm of chaos.