Chinese New Year: The Biggest Celebration on Earth

Every year, Chinese New Year sees the largest annual mass migration of humans on the planet, when a sixth of the world's population travel home to celebrate with their families. That's 1 billion people making 3.7 billion journeys over a 40 day period. Railway stations, bus depots and airports heave with the strain and it happens at a time of year when the weather is harsh and unpredictable. It is an immense occasion - celebrated publicly and privately and offers an amazing window into the heart of what it is to be Chinese in the 21st century.