Each year, thousands of North Koreans risk their lives to escape poverty and oppression in their Stalinist nation.  Most travel through China, which does not welcome them. Their destination is usually South Korea and the United States - often via Thailand.  It is a perilous journey that can take months or years.  VOA's Luis Ramirez followed the trail of North Korean refugees, traveling from China's border with North Korea to Thailand where they wait to make the final escape to freedom in South Korea or the United States.  In the first of a four-part series, he looks at the defectors' treacherous and painful journey.

A view of life in North Korea, secretly shot from a military zone on the Chinese border.  A barbed wire fence is China's first line of defense from what Beijing fears could be an onslaught of refugees.

?It was much too difficult to live," says one North Korean defector. "We had nothing to eat.  We could not get any money by doing what the government recommended we do."

A 34-year-old woman says she, like thousands of others, came to the Tumen River that separates North Korea and China and walked across the shallow waters in search of food and freedom.

The risks are enormous.  On the North Korean side, soldiers patrol with rifles. But reaching this border signpost - seen here from the North Korean side - is not the end of danger for escapees.

China does not want a flood of refugees.  To avoid hurting relations with its fellow Communist leaders in North Korea, and to discourage defectors, Beijing regularly sends them back. 

Christian missionaries have for years been the main link in the secret trail for defectors.  Reverend Douglas Shin, a Korean-American pastor from Los Angeles, California, is among those who have helped North Koreans hide from Chinese police - and from others who prey on them. 

"If you don't know anybody in China, if you don't have any sort of welcoming party, you are in trouble.  You just can't survive there anymore because the crackdown is so severe and the bounty or reward is so high," he said.

Cold and alone, the woman had no one to turn to when she reached a Chinese village.  She recalls, "I came to a house, knocked on the door, and a woman came out.  I told her I came to China to earn money. She said, 'OK, I will give you a job, maybe in a restaurant.'  She took me to another place, and when I arrived there I found a group of men standing around me. I then learned I had been sold to them.?

Women fleeing North Korea are often victims of sexual slavery.  They are trafficked to work in karaoke bars, as prostitutes, or doing the jobs that others do not want.

Activists estimate 70 percent of North Koreans who flee are women - and that slavery is common in areas like China's Yanbian Korean Autonomous Region and other northern Chinese areas near the border with North Korea.