A green dress. A green sundress covered in sand. A green sundress drenched with water up to the waist and covered in sand. A mother clutching an under-1-year-old child, looking frantic and pale in a green sundress with water up to the waist covered in sand, staggering down the beach past my family and me.

My sister and I could see the terror on this poor woman’s face. We knew that look – that fear, the absolute terror.