China invented paper money more than a millennium ago during the Tang Dynasty (618-907), and Chinese innovators are now at the forefront of technological changes that could abolish cash for good. With banknotes rapidly going out of fashion in the electronic age, China's Alipay just made it even easier for consumers to spend their money by rolling out facial recognition payments.

In the first commercial application of the technology at a fast food restaurant in Hangzhou, East China's Zhejiang province, customers can now settle the bill by having their face scanned by a so-called "Smile to Pay" app.

It took hundreds of years for the concept of paper money to spread from China to the rest of the world, but the modern pace of technological uptake means facial recognition payments will not be confined to China for very long. Just 50 years after the world's first cash dispenser was installed in suburban London, subsequent generations have become accustomed to dispensing with physical money almost entirely and using their charge cards for everything.