Hans Christian Andersen 
The Little Mermaid and Other Tales 

The Little Mermaid lives in an underwater kingdom with her father, the sea king; her grandmother and her five elder sisters, each born one year apart. When a mermaid turns 15, she is allowed to swim to the surface to watch the world above, and as the sisters become old enough, one of them visits the surface every year. As each of them returns, the Little Mermaid listens longingly to their various descriptions of the surface and of human beings.