Lifeguards rescued 65 people who were being pulled out to sea by a freak rip current in Cornwall.
The sudden strong current pulled holidaymakers away from the shore, and lifeguards at Perranporth beach had to launch a mass rescue operation.
Another 15 people were saved in Porthtowan. Beaches were packed because of the sun and school holidays.
If it had not been for the lifeguards' quick action, "we would have seen people drown", a spokesman said.
"It was quite extreme and we had to act quickly," said beach manager Andy Thomas.
Everyone was rescued and no-one was badly hurt.
Twelve lifeguards used boats and rescue floats to save the swimmers on Perranporth beach on Sunday.
Movement of sand
Lifeguards in Cornwall have now warned people to pay attention to the flags on the beaches, which tell you if it's safe to go into the sea and exactly where you can swim.
Rip tides happen when there is a sudden movement of sand under the water which means people can suddenly find themselves out of their depth.
Although rip currents are quite common, the lifeguards at Perranporth said they couldn't remember one happening on that beach before.