Tyndall glacier (Photo: NPS/Jacob W. Frank)

Back in October, 200 million tons of rock slid down a valley and onto a glacier in an isolated part of eastern Alaska. It was the largest landslide in North America since Mount St. Helens erupted in 1980, the Associated Press reports. And almost no one noticed. 

The landslide had a magnitude of 4.9, which is not too far out of the ordinary. The activity registered on sensors that Columbia University scientists had set up to detect seismic activity. They confirmed its existence with satellites, and reported their finding this December.

One potential factor in the landslide was that the glacier in this area, the Tyndall Glacier, has retreated 10 miles since the 1960, leaving the ground below exposed and weak. Climate change may have also contributed.

On Sunday in Shenzhen, China, though, there was a landslide that was much more clearly man-made. There, people had created what the AP describes as “a mountain of construction waste material and mud.” It had reached 330 feet when heavy rain caused it to collapse and flood into an industrial park. 

More than 70 people are still missing, the AP says. But one lucky man was pulled out of the wreckage 60 hours after the landslide. He had broken a hand and a foot. But he survived. 

Bonus finds: Secret 500-year-old Polish gingerbread recipe, tiny, golden Tudor treasures, forgotten slides of 19th century telescope images

Every day, we highlight one newly lost or found object, curiosity or wonder. Discover something unusual or amazing? Tell us about it! Send your finds to [email protected].