No matter how much you complain about your journeys around Thanksgiving or Christmas, the travel done around China's public holidays almost certainly puts it to shame. For many workers, these public holidays are the majority of the vacation time they will get all year. And for the migrant workers who moved away from their families, it's usually time for an arduous journey over many hundreds of miles from the big city to home.

The two biggest holidays of the year are the so-called "Golden Weeks" based around the National Day in October and the Lunar New Year celebrations in February. We're in the latter right now. To get a sense of the travel madness, Chinese Web-giant Baidu created a real-time heat map of the enormous holiday migration in China. You can see it for yourself here.

To create the map, Baidu used location data collected from users of their mobile app. For example, if the app says someone is in Shanghai on Tuesday morning, then out in the rural provinces by the evening, its safe to assume they are probably heading home for the Chinese New Year (which falls on Feb. 19 this year). The map also has flight data and other information.

It's not a complete picture, of course — not everyone has the Baidu app on their phone, and in a rough 40-day period around the Lunar New Year, almost 3 billion passenger trips are likely to be made. But by using data from the 350 million users of the Baidu app, we can see clear patterns in migration.

Major cities like Beijing, Shanghai and Guangzhou become clear hubs for people leaving the city. In the next few days, the map will probably show people returning to these cities. There are said to be more than 260 million migrant workers in China, many of whom left their homes behind to take low-paying jobs in enormous cities.

It's fascinating to watch this massive internal migration in action. “You're basically looking at the serious intensity of travel in this holiday," Baidu spokesman Kaiser Kuo told the Associated Press. “It’s not just the world’s biggest human migration, it’s the biggest mammalian migration."

Of course, the potential for disaster is high, and a stampede in Shanghai that left 36 dead in September has made officials extra cautious this year. But most of the time, the mass migration ends up being annoying rather than life-threatening (as photos of Golden Week traffic jams can attest).  “It’s a sight to behold," Kuo explained. "It’s quite miraculous that nothing goes terribly wrong.”