28 Nov 2013, Berlin, Germany — Illustration – A Bitcoin coins pictured at the coin dealer BitcoinCommodities in Berlin, Germany, 28 November 2013. When paying with bitcoin, no actual monetary exchange takes place between buyer and seller. Instead, the buyer requests an update to a public transaction log, the blockchain. Photo: Jens Kalaene — Image by © Jens Kalaene/dpa/Corbis