Some 15 years ago me and my sister (we were in our late teens/20s) were swimming in the sea when it's rather rough/windy, and she was pulled away from shore by a current.

I swam out to get her but all I could do was to keep us barely afloat, didn't have enough strength to fight the current to get back, and it was so far away from shore I thought no one could have seen us.

We struggled for like 15 minutes, completely exhausted and there was a moment when I thought that was it, that we're gonna die here.

Suddenly several men wearing swim fins, probably locals, swam to us and together they got us back to shore.

We were lying on the beach, shaking from cold and fear.

When I got a moment to catch my breath and turned around, these men were gone, we didn't even have a chance to thank them.

That incident has stuck with me ever since.