Kreuzberg (From Wikipedia, the free encyclopedia)

Kreuzberg, located south of Berlin-Mitte, is one of the best-known boroughs of Berlin, famous for its nightlife and its left-leaning electorate as well as its problems with criminality, the drug scene and a very high number of immigrants.
Kreuzberg consists of two different parts, the south-eastern 'SO 36' (or simply '36') part and the south-west 'SW 61' (or simply '61'). Until the wall fell, these were the last two digits of the postal codes for the two areas.
It was a separate borough until Berlin's 2001 administrative reform, when it was combined with Friedrichshain to form the new borough of Friedrichshain-Kreuzberg. Since these two localities are linked only by a single bridge over the Spree river, the Oberbaumbrücke, this combination seemed awkward to many residents. The two areas could not agree on a common location for the future borough's city hall, so the present location in Friedrichshain was decided by tossing a five-Mark coin.

May Day graffiti in Kreuzberg. The text reads, "May 1st: Cars burn, cops die".
Kreuzberg is known to many for numerous Turkish immigrants from eastern parts of Turkey, and the yearly May Day riots. Both stereotypes result from the fact that before the fall of the Berlin Wall in 1989, Kreuzberg was in an isolated position with its eastern parts almost entirely surrounded by the Wall. This area consequently had cheap rents and attracted lower-income families as well as squatters from the radical left. The western part of Kreuzberg also bordered onto the wall, and it was here that Checkpoint Charlie was, and also nearby the place that first wall victim Peter Fechter was trying to cross to when he was killed.
Kreuzberg has sometimes been called the largest Turkish city outside of Turkey. In 1999, of its 146,884 inhabitants, 49,010 did not have German citizenship (of which the large majority was Turkish). However, in the upmarket areas such as Bergmann Kiez or Wrangel Kiez this is really no longer the case with a cosmoplitan crowd of students, young professionals and young couples. Especially in the eastern part of the borough, the streets have a distinct, almost oriental flair. Still today, streets like the Oranienstraße are full of restaurants and bars, offering food from many places of the world. Kreuzberg has also big problems with gang criminality induced by wars in the middle east. One of the best known gangs of muslims are "The Warrior$ 36" around the Wrangel Kiez. The song "Kreuzberg" appears on Bloc Party's album A Weekend in the City.
Kottbusser Tor (Metro train station)
While Kreuzberg thrives on its diverse cultures and is still an attractive area for the younger, alternative type of person, the district is also characterized by high levels of structural unemployment and income levels are among the poorest of Berlin.

As opposed to other localities of Berlin, which mostly originated in older villages, Kreuzberg is not much of a historical entity. Instead, it was only formed as such in 1920 with the formation of Berlin in today's borders. Its name is simply that of its highest elevation – the Kreuzberg (literally, "cross hill") of 66m above sea level, a traditional place for weekend trips with small restaurants, which received its name from an 1821 monument by Karl Friedrich Schinkel remembering the liberation wars against Napoleon I of France. Except for its northernmost part, today's "Kreuzberg" – which even didn't exist under that name – was a very rural place until well into the 19th century.
Bridges over the Landwehrkanal in Kreuzberg
This changed when, in the 1860s, industrialization caused Berlin to grow explosively. This called for extensive housing – much of which was built exploiting the dire needs of the poor, with widespread land speculation. Many of Kreuzberg's buildings originate from that time. Far into the 20th century, Kreuzberg was the most populous of Berlin's boroughs even in absolute numbers, with more than 400,000 people, although Kreuzberg was the smallest of the boroughs. As a result, with more than 60,000 people per square kilometer, Kreuzberg had the highest population density in Berlin and consequently probably the worst living conditions.
In addition to housing, Kreuzberg was also one center of Berlin's industry. The so-called Exportviertel along Ritterstraße consisted of many profitable small businesses, and the "press quarter" along Kochstraße was the home of most of Germany's large newspapers as well as the Ullstein, Scherl, and Mosse book publishers.
Both of these industrial quarters were almost entirely destroyed during World War II, with the bombings of a single night from February 3, 1945. In remembrance of the old tradition, the Axel Springer press company erected its German headquarters at Kochstraße again, right next to the Berlin Wall.
Schlesisches Tor (Metro train station), Kreuzberg
After World War II, Kreuzberg's housing rents were regulated by law, which made investments unattractive. As a result, housing was of low quality, but cheap, which made the borough a prime target for immigrants coming to Germany (and Berlin).
Since the fall of the Berlin Wall, Kreuzberg found itself suddenly in the middle of the city again. Although the borough still has social problems, it is no longer quite the ghetto it used to be. Instead, the initially cheap rents and many 19th century housing made some parts of the borough more attractive as a residential area even for prosperous people: lawyers, doctors and small businesses have moved there. Today, Kreuzberg has one of the youngest populations of all European city boroughs; statistically, its population has been swapped completely twice in the last two decades.