The 850 meter dam is visible from satellite imagery and is also most likely the longest beaver dam in the world. The previous record was held by 652 meter structure in Montana. This one has been spotted in Wood Buffalo National Park in northern Alberta.
The dam was in fact spotted by Ecologist Jean Thie, who is executive director of the Canadian Institute of Geomatics and discovered the 850-metre long dam while scanning satellite images for signs of climate change.