A person holds a tablet computer showing the app of the Reserve Bar Stock Exchange, which is used for ordering drinks, in the City of London, Britain July 3, 2015. There is no shortage of liquidity at London's first stock exchange-themed bar, where beer prices fluctuate with demand and the occasional market crash can send prices tumbling. With its sterile white walls, piercing ceiling lights and flatscreen TVs flashing green and red, Reserve Bar Stock Exchange in the 'Square Mile' financial district has the feel of a trading room. Photograph taken July 3, 2015. REUTERS/Peter Nicholls