Liquidity and low latency exert a 'gravitational pull' on trading engines that draws them towards the key urban centres. Traders may be able to access liquidity worldwide, but colocation and proximity hosting are still key for brokers aiming for 'near-zero' best execution. The big challenge, though, is not just to identify the strategic liquidity centres of today, but to commit resources towards those with long-term durability. That means finding the liquidity centres capable of maximising their 'connectivity spread' - not least, optimising their green-field resources - to ensure long-term success. Focusing primarily on Europe, and in particular London, Bob Giffords charts the current and future evolution of the global trading landscape.