Earlier this year, 7-Eleven opened its first fully-automated store. It is located in Seoul, South Korea, in the world's 5th largest building. For now, it's only open to employees of Lotte, owner of Korea Seven. But soon, fully-automated stores could open everywhere.

Cash is still king in many countries, even with the advent of debit and credit cards. But now cash and card payments are facing a challenge from new foes - smartphones and social platforms. With over one-third of the world having access to smartphones, and their high penetration in developed countries, will we still need to carry our wallets around?