Without hundreds of millions of migrant workers, China's 40 years of economic growth wouldn't have been possible. The fruits of their labor are evident in cities like Dongguan, which has become a global manufacturing hub. The city's young workers spend nearly 12 hours a day in factories, but there is always time to find love. Our reporter Ge Yunfei has more.

"Get up! It's 7:30 !"

It's early in the morning, and time for Bai Jinying to wake up her husband Wang Shaojun. The two 23-year-olds have been married and living in this 10-square-meter apartment for two years. The rent is only 200 yuan, or about 30 dollars, every month. After having a simple breakfast, they're ready for work.

"Hurry up or we'll be late."

Six years ago, Wang left his hometown—a small village in China's southwestern Sichuan Province. It's a less developed province two thousand kilometers away, and an important source of China's migrant workforce. The 17-year-old young man headed for Dongguan, a manufacturing hub in China's richest Guangdong Province, looking for opportunities to change his life. Then, Wang met Bai, a countryside girl. Similar backgrounds brought them close and soon the two fell in love.

BAI JINYING "At first my mother thought his hometown was too far away. But I told my parents, happiness instead of distance is what really matters. This boy was really good to me. He could give his everything to me. He told me that my happiness is his happiness. So my parents finally accepted him."

Over 8 million people are living in Dongguan but a big city has a lot more to offer than their small hometown villages. But for this couple, it is their first time going to an amusement park. The young husband said one day he will make it up to his wife.

WANG SHAOJUN "In the future, if we can make more money, I hope I can take her to different places, to see the deep seas, to climb high mountains, to travel around the world. That's my biggest wish."

Now the two are working at a lamp factory. Wang is a technician drawing lamp prototypes. Bai is a quality inspector on the assembly line, checking over thousands of lamps every day. She says it's all for her daughter and family.

BAI JINYING "My child needs milk powder. My sister is studying in a university. And my parents' income isn't stable. We need to support them. So I need to work very hard."

For the young couple, the only family time is at night after work with their two year-old daughter Xiaoru on video talk. Xiaoru has been in Wang's hometown with her grandparents ever since her birth.

BAI JINYING "I really miss her a lot. It really hurt me and made me want to cry when I saw she had a cold."

Reporter: "Have you ever thought about bringing her here?"

BAI JINYING "Yes. But that would cause too many problems for her."

The couple are too busy to take care of the baby. They only get to see her once a year, during the Spring Festival holiday. In fact, as second-generation migrant workers, Wang was born in Dongguan but was also raised in his parents' village. But he doesn't want this cycle of migration to continue.

WANG SHAOJUN "In ten years, I want to move back to my hometown. It's gradually developing and the government has lots of preferential policies. Maybe I would open a small store, or raise some pigs or chickens. Then all my family can be together. That's what I've always wanted."

The young couple say they just want to create a better life for their child. That's exactly the same wish that has been pushing millions of migrant workers to Dongguan over the past four decades. Their journeys have brought, and continues to bring, great changes and rapid growth throughout the country. Ge Yunfei, CGTN, Dongguan.