This is a swimming pool at a resort in Algarobos. The ocean beaches have such a strong rip tide that they built this pool as swimming isn't allowed on the beach. It is the largest swimming pool in the world covering 19 acres. It is about a mile long.
There are about 8 buildings in the resort, but the each room is owned by an individual and they rent them. The only problem is that you have to bring your own sheets and towels. It doesn't seem like a good deal for $300 a night.