(CNN) — It's the largest annual human migration in the world.
Each year between late January and early February, hundreds of millions of Chinese people head home for the country's biggest holiday...the Lunar New Year.
Also called the Spring Festival, it's the one time each year when families scattered across the country reunite.
And to get to one another, China sees a travel frenzy on a massive scale as millions of Chinese working in distant parts of the country struggle to get home.
Some 1.41 million passengers left Guangzhou by train Thursday, setting a new record for the city during the Lunar New Year, which begins Monday.
Luo Haohan, a product development engineer, and his two sons were among them.
Before boarding the train, they had to walk four kilometers as the huge crowds forced the subway to close. They expected their whole journey to take 16 hours.
This year, the government expects a phenomenal 2.9 billion trips to be made across the country.
The annual migration has boomed right along with China's economy over the past 30 years.
Factory towns needed workers, with most coming from China's rural villages. Hundreds of millions of people spend the year away from their families, but the pull of home during the holiday is something few can resist.
Lu Rongxu, a worker in a furniture factory, returns home to Sichuan in western China to see her elderly parents once a year. Her children are also migrant workers in cities far from home.
When we speak, she's perched on her suitcase about to embark on a 20-hour train ride -- her entire journey home will take three days.
"It's alright, it's not too exhausting. I simply want to have meals with everyone in the family, that's all."
Once home, traditional dinners are held, and Chinese children receive little red envelopes, filled with cash that's referred to as "lucky money." On Lunar New Year's eve, roughly 700 million people watch a celebration broadcast on state TV.
After the Spring Festival ends, most people return to work and cities fill right back up. Though there are many who take extended vacations.
The Lunar New Year holiday runs less than 10 days, but the peak travel period runs nearly six weeks.