In the United States, Memorial Day weekend usually marks the beginning of summer vacation. Kids break free from the shackles of their desks and embark on a two-month long journey of sleeping in, summer camp and video games.
We're so jealous.
But in some places in China, school vacations aren't as big a cause of celebration.
Millions of parents leave their village homes and families to find work in the city. They come home only once a year to see their children during the Chinese New Year.
This annual homecoming is the largest migration of humans in the world.
Here, Lin met the sons and daughters of these working parents. The students lived at the school during the week. On weekends they stayed with their grandparents and sometimes, if they were lucky, their mothers too.
"In China we call them 'left-behind children,'" Lin said. "The children are lonely. Their hearts are frail."
Lin documented how the students spend their time alone in the following slideshow.
Click through to see that these "left behind children" are like kids everywhere. They run around outside, play with toys and hang out with friends.
But the kids in these photos may not have a parent call them inside for supper.
-- Helen Anne Travis