Avoca Rocks, New South Wales, Australia.
High tide and a fairly big swell produced this washing machine like zone near the ocean. As the swell washed out, these teenagers jumped or slid into the turbulence. They were usually under for 5 seconds or so and then popped up disorientated and then waited for the next swell to wash them back in.
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https://www.youtube.com/watch?v=xcZMqvUbXjc