The world's largest annual migration is underway as hundreds of millions of Chinese people head back home to celebrate the Lunar New Year with their families. The week-long holiday is surrounded by a 40-day travel frenzy known as "Chunyun", during which the total volume of passengers this year is expected to be almost three billion. That's about two journeys for every single member of China's population.

Bus terminals, train stations and airports will be pushed to their limits as they try to cope with the massive increase in passengers. Delays can lead to meltdowns. In 2016, around 100,000 people were left waiting at Guangzhou Railway Station overnight after train services were cancelled due to heavy snow. In this gallery, we present Spring Festival travel scenes from the last few years to give an idea of what passengers may face this year.

Lunar New Year, also known as the Spring Festival, is the most important holiday in China. Many people work in big cities hundreds of miles from their home towns, and the week-long national holiday is the only time in the year that they can see their families.