This story first appeared on the website of NBC News’ partner Sky News.

DERNA, Libya — Locals now call Wadi Derna “the dam of death.”

In a moment’s notice, the structure unleashed tens of millions of cubic meters of floodwater on Derna’s residents.

The torrents swept generational homes and entire families into the Mediterranean sea — leaving onlooking survivors in a state of shock and horror.

The scene at one of the dams that collapsed in heavy rains and sent a massive flood gushing into the eastern Libyan port city

As we walked across the emptied river bed, residents stood on the precipice of the cliffs.

Their eyes stuck on what was once the dam.

A collapsed ridge of concrete and a debris-filled cylindrical pipe flung to the side.

A road that connected the valley is now shredded — the two sides of asphalt reaching over the edge to each other.

This is a site of swift colossal damage.

“We will never forget what happened here,” says Safwat Ashraf, a 24-year-old teacher.

“Our community feels destroyed. It’s a small tight-knit city where everyone knows each other. Our friends and families are all gone.”

His house is on one of the higher plains. Across from their home, a primary and secondary school sits battered on the valley’s edge. Its wall was ripped apart and thrown into the river bed.

Safwat says he heard women and children screaming who had sought shelter in the school.