For the first time in over two years, California's captivating 'glory hole' of sinking water has been activated after weeks of heavy rain.
The circular Morning Glory Spillway on Lake Berryessa in northern California has consistently fascinated onlookers on the rare occasion it is used to drain water from the Monticello Dam.
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The spillway is 22 metres wide and its drain is 75 metres long, making it one of the largest of its kind in the world. Water levels have only been high enough to activate the hypnotic drain three times in the past 13 years.
Drone footage captured from when the spillway was activated in 2017 shows water flooding over the sides and plummeting down the tube.
In 1997 a woman died after coming too close to the hole. The San Francisco Chronicle reported at the time that the swimmer gripped the edge of the hole for twenty minutes before falling to her death.