Many people are moved by Chen's story and join his volunteer work

Every weekend in the past 13 years, Chen Si would ride an electronic scooter for 20km (12.4 miles) from his home to China's most frequented suicide spot - come rain or shine.

The 48-year-old man, a worker at a logistic company, makes the weekly trips at his own expense to prevent troubled souls from jumping off the Nanjing Yangtze River Bridge, a gargantuan structure spanning across China's longest river.

'By saving these desperate people, I feel like I am saving the past self,' said Mr Chen, who was once a frustrated migrant worker in the metropolitan city of Nanjing.

Heroic: Chen Si dedicates his life to preventing suicides on the Nanjing Yangtze River Bridge. Above, Chen tried to save a man on May 16, 2004

Bravery: The 48-year-old man, a worker at a logistic company, volunteers to help the others. Above, Chen tried to save a man on May 16, 2004

Famous structure: The double-deck rail-road bridge in eastern China was completed in 1968

The Nanjing Yangtze River Bridge has always been one of the most famous bridges in China.

Completed in 1968, the double-deck rail-road bridge was once the symbol of Communist China's industrial power.

But it's also believed to be China's most frequented suicide spot with pedestrian platforms situated 60 metres (197 feet) above the fast-flowing Yangtze River.

Statistics showed that more than 2,000 people had committed suicide from the Nanjing Yangtze River Bridge between 1968 and 2006, according to People's Daily Online.

Since 2003, Mr Chen, who is originally from a rural village in Suqian, has saved 321 lives, many of whom were desperate migrants who saw no future in the city and was too ashamed to go back to their hometowns.

With every saving attempt, Mr Chen used all his might. He talked, he grabbed, he held strangers in his arms until they stopped struggling.

'I was once one of them,' said Mr Chen in an interview with MailOnline. 'I was helped by a kind-hearted countryman when I faced hardship working as a vegetable seller in Nanjing. '

The man, who speaks Mandarin with a heavy local accent, added: 'When my life got better, I wanted to help the others find hope.'

Mr Chen stood next to his signboards on the bridge in March, 2004. On one of his signboard, he wrote: 'Treat every day of our life with kindness'

Dedicated: The man has patrolled the bridge every Saturday and Sunday for 13 years

Quick-thinking: He has has saved 321 lives, many of whom were desperate migrants

Selfless: Mr Chen is originally from a rural village in Suqian and moved to Nanjing in 1990

Mr Chen said he came from an impoverished village and moved to Nanjing in 1990 - among his luggage he brought 50kg (110lbs) of rice with him to make sure he would not starve in the strange city.

As the provincial capital of Jiangsu, Nanjing is one of the most modern and historic cities in China.

With more than eight million residents, the former Chinese capital boasts ruins of an ancient palace and a glitzy 450-metre-tall (1,476 feet) skyscraper.

However, the glamorous city is also an easy place to get lost for migrants.

'Sometimes, you face difficulty while living alone away from your home, all you need is a little encouragement from the others,' Mr Chen said.

During his first five years in Nanjing, Mr Chen's life was hard. Working as a construction worker then a vegetable seller, he couldn't afford to rent a good house and had trouble finding a girlfriend.

Then a friendly countryman gave him advice, encouraging him to open his own grocery store, through which Mr Chen managed to build a life. He got married and in 1997 he had a daughter.

After watching the frequent suicidal attempts on the Nanjing Yangtze River Bridge on the news, Mr Chen wanted to offer his help to these people - like what his friend had done to him.

There were media reports claiming Mr Chen once contemplated suicide on the bridge himself.

The man denied: 'I have never thought of killing myself even when I was a lowly vegetable seller.'

Mr Chen was shocked by the frequent suicidal attempts on the Nanjing Yangtze River Bridge

The man is pictured with his fellow volunteers who work with him to prevent suicides in 2016

Mr Chen patrols on the bridge every Saturday and Sunday from 8am to 5pm. He has help from two local universities, whose psychology students would provide free counseling services to those in need.

The man still remembers his first day as a volunteer on the bridge.

'It was September 19, 2003. I rode past the bridge, then I told my wife I would go up and take a look if anybody would need help,' he said.

He stayed on the bridge the whole day and managed to save one person in the afternoon. Mr Chen said that man, surnamed Wang, told him that he lost hope in life because he had been wrongly convicted and had been imprisoned for two years.

Mr Chen convinced Wang to get off the railing, escorted him to the foot of the bridge before writing him a note agreeing to help him prove his innocence.

'When I saved him, I did not have experience. But now I could tell whether or not someone is contemplating suicide by looking at their back,' said Mr Chen.

'Usually their head, shoulders, buttocks and legs are completely still because they only have one thought in their mind: death.'

Most of the people he saved faced one of the five issues: mental illness, emotional trauma, debts, domestic violence or terminal illness.

He said the hardest people to talk down are those dealing with domestic violence or terminal illness because it is hard for them to 'see past the hurdle'.

Day in and day out, Mr Chen guards the platforms of the bridge trying to bring people from the verge of death.

The man's selfless practice has moved people from around the world. In 2015, his stories were turned into an award-winning film, 'Angel of Nanjing', by directors Jordan Horowitz and Frank Ferendo.

Chen Si travels 20km (12.4 miles) from his home to Nanjing Yangtze River Bridge

He rides his electric scooter when he goes to patrol the bridge from 8am to 5pm

Nanjing Yangtze River Bridge (pictured) is believed to be China's most frequented suicide spot

More than 2,000 people had committed suicide from the Nanjing Yangtze River Bridge between 1968 and 2006. Above, policemen saved a suicidal woman in 2003

On September 19, Mr Chen commemorated the 13th anniversary of his volunteer work on the bridge.

He posted a blog, A Bridge Journal, listing the meaningful figures to him.

He had successfully stopped 321 people from attempting suicide, provided assistance to 280 people who were in need of help and spent 12,650 hours looking after those he had saved.

The volunteer work had cost him 748,750 yuan (£86,813), part of which had been covered by charity groups.

Mr Chen not only saves people, but also helps them to regain confidence in life.

He has rented a two-bedroom flat to the north of the Yangtze River so that those in need could have a place to stay after being saved from the bridge.

The flat costs 1,000 yuan (£116) a month. Two-thirds of the cost is covered by donations and Mr Chen pays the rest.

With a monthly salary of 4,000 yuan (£464), he spends half of the money on his volunteer work and hands the rest to his wife.

'I can't say my wife is happy about my volunteer work,' Mr Chen told MailOnline. 'Who would want their husband to spend this much money on strangers?'

But looking forward, Mr Chen said he would carry on his work.

'I'm nearly 50 years old. I can't say I will do this forever because I don't want to give myself too much pressure. But I will certainly try my best.'

The Nanjing Yangtze River Bridge used to be the poster image used by the Communist rulers - because it was the first bridge they were able to build on their own across the iconic Yangtze River.

But now, the structure has evolved to represented hope and faith - because of Mr Chen who believes that 'we should treat every day of our life with kindness'.

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