Published on 18 Oct 2013 | Within just a few months, Berlin has become the capital of the digital currency Bitcoin. Invented in 2009 by an anonymous hacker, it has not only become an online hit, but in the trendy district of Kreuzberg, more than twenty businesses now accept payment with the currency. Thousands of online merchants are starting to use it, to the point where banks are considering it a force to be reckoned with.