U.S.A. Too much water: this Californian lake doesn't end up emptying itself in its gigantic "Glory Hole"

In the heart of Napa Valley, a circular structure 22 meters in diameter, which has only been activated 25 times in 70 years, forms a hypnotic vortex that looks like it was taken from a science fiction film.

It's a monstrous 21-metre-diameter hole created by man's hand in the 1950s. It's a cavity used to evacuate water from Lake Berryessa, north of California, to prevent it from overflowing... a bit like the siphon of a bathtub. It's been activated for a few days, and the show is phenomenal.

Discover why this incredible hole intrigues and amazes thousands of internet users. A phenomenon as impressive as unexpected.