Answer: The arrival of the Israelites to the Red Sea
More information: The last day of the Passover celebrates the arrival of the Israelites (who had successfully escaped slavery in Egypt) to the Red Sea. It's noteworthy to mention that upon getting to the Red Sea, Moses miraculously parted it for the Israelites to get across. During the last day of Passover, women and girls customarily light candles in commemoration of that great event.