As China faces pressure to develop green energy sources, families in the path of construction are being forced to give up their homes. The BBC's James Reynolds travelled to the village of Gongtan, near the south-west city of Chongqing, to hear their stories.
Xia Ping, left, says his home has been in his family for 300 years
Halfway up a valley, a team of Chinese Noahs prepares for a flood.
Builders pile roof tiles into baskets and carry them up the hill.
The Communist Party has given orders: Take down all the houses on the hillside. There is no argument and no debate - when the Chinese government makes up its mind to do something, it gets it done.
'Nowhere to sleep'
In the next few months, the government will flood the Wu River below the houses to power a new dam built downstream.
The river level will rise more than 50m (164ft), so the houses halfway up the hillside will disappear under water.
That means Xia Ping will lose the home that has been in his family for more than 300 years.
He is paying builders to take his house apart and re-assemble it further up the hill. The government is paying him some compensation - but he says it is not enough.
"They've forced us to move," he said. "I feel like a farmer who's lost his cow and like an eagle who's lost his sky. I can only say one sentence - I am very sad."
His neighbours come by to talk. They sit in Xia Ping's dining room - its doors open to the valley below.
"We don't have anywhere to sleep," said one man. "We don't have anything to eat. The government doesn't care."
Another neighbour sitting across the table nods his head.
A few minutes later, the police arrive. They have heard that the foreign press has come here - and they are keen to keep a close eye on all outsiders. They note down our names and passport numbers.
We wait for the police to leave and then we head on to our next destination. The residents of a remote village further along the river have called us to see them - they are desperate to talk.
We drive for more than an hour along a muddy road. We get to a shaky wooden bridge suspended high above the river - it is the only way into the village. The driver tells us to walk across it one by one. We walk slowly - the bridge sways with every step we take.
We get in and find the village being taken apart.
"The government gave us just one month to take down our houses," said Dai Yin Xiang. "They will force us."
"They will force us," repeated Ran Qi Bai, standing next to her. "We weren't told what they were planning. They just came in like robbers, telling us what to do. Some of us still haven't signed any documents."
But that does not appear to matter. Villagers here have just a few days in which to take down their houses. One family has taken down its bathroom walls - and now has to wash in the open air. Another family is living in a converted pig sty.
The government has promised to build new homes for the village, just up the hill. But the new homes are not yet ready. For now, many people here simply have nowhere to live. And they have no right of appeal.
The world wants China to turn to green energy, so China builds dams. And the villagers by the side of the river have to pay the price.