Nereids, mer-people, water folk, mermaids, whatever you want to call them, all cultures around the world have within their histories some version of half-human half-fish creatures. From the German Lorelei, the Icelandic Marmenill, the Matsyanaris in India to the Babylonian fish god, the Polynesian god Vatea, or the African Yemaya, the oceans and rivers of our planet are swimming with mysterious creatures. So the next time you’re swimming in the ocean, take care! You never know who – or what – you’ll meet.